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rename from test/css/samples/omit-scoping-attribute-id/input.html
rename to test/css/samples/omit-scoping-attribute-id/input.svelte
diff --git a/test/css/samples/omit-scoping-attribute-whitespace-multiple/expected.html b/test/css/samples/omit-scoping-attribute-whitespace-multiple/expected.svelte
similarity index 100%
rename from test/css/samples/omit-scoping-attribute-whitespace-multiple/expected.html
rename to test/css/samples/omit-scoping-attribute-whitespace-multiple/expected.svelte
diff --git a/test/css/samples/omit-scoping-attribute-whitespace-multiple/input.html b/test/css/samples/omit-scoping-attribute-whitespace-multiple/input.svelte
similarity index 100%
rename from test/css/samples/omit-scoping-attribute-whitespace-multiple/input.html
rename to test/css/samples/omit-scoping-attribute-whitespace-multiple/input.svelte
diff --git a/test/css/samples/omit-scoping-attribute-whitespace/expected.html b/test/css/samples/omit-scoping-attribute-whitespace/expected.svelte
similarity index 100%
rename from test/css/samples/omit-scoping-attribute-whitespace/expected.html
rename to test/css/samples/omit-scoping-attribute-whitespace/expected.svelte
diff --git a/test/css/samples/omit-scoping-attribute-whitespace/input.html b/test/css/samples/omit-scoping-attribute-whitespace/input.svelte
similarity index 100%
rename from test/css/samples/omit-scoping-attribute-whitespace/input.html
rename to test/css/samples/omit-scoping-attribute-whitespace/input.svelte
diff --git a/test/css/samples/omit-scoping-attribute/expected.html b/test/css/samples/omit-scoping-attribute/expected.svelte
similarity index 100%
rename from test/css/samples/omit-scoping-attribute/expected.html
rename to test/css/samples/omit-scoping-attribute/expected.svelte
diff --git a/test/css/samples/omit-scoping-attribute/input.html b/test/css/samples/omit-scoping-attribute/input.svelte
similarity index 100%
rename from test/css/samples/omit-scoping-attribute/input.html
rename to test/css/samples/omit-scoping-attribute/input.svelte
diff --git a/test/css/samples/pseudo-element/input.html b/test/css/samples/pseudo-element/input.svelte
similarity index 100%
rename from test/css/samples/pseudo-element/input.html
rename to test/css/samples/pseudo-element/input.svelte
diff --git a/test/css/samples/spread/input.html b/test/css/samples/spread/input.svelte
similarity index 100%
rename from test/css/samples/spread/input.html
rename to test/css/samples/spread/input.svelte
diff --git a/test/css/samples/supports-query/input.html b/test/css/samples/supports-query/input.svelte
similarity index 100%
rename from test/css/samples/supports-query/input.html
rename to test/css/samples/supports-query/input.svelte
diff --git a/test/css/samples/universal-selector/input.html b/test/css/samples/universal-selector/input.svelte
similarity index 100%
rename from test/css/samples/universal-selector/input.html
rename to test/css/samples/universal-selector/input.svelte
diff --git a/test/css/samples/unknown-at-rule/input.html b/test/css/samples/unknown-at-rule/input.svelte
similarity index 100%
rename from test/css/samples/unknown-at-rule/input.html
rename to test/css/samples/unknown-at-rule/input.svelte
diff --git a/test/css/samples/unused-selector-leading/expected.html b/test/css/samples/unused-selector-leading/expected.svelte
similarity index 100%
rename from test/css/samples/unused-selector-leading/expected.html
rename to test/css/samples/unused-selector-leading/expected.svelte
diff --git a/test/css/samples/unused-selector-leading/input.html b/test/css/samples/unused-selector-leading/input.svelte
similarity index 100%
rename from test/css/samples/unused-selector-leading/input.html
rename to test/css/samples/unused-selector-leading/input.svelte
diff --git a/test/css/samples/unused-selector-ternary/expected.html b/test/css/samples/unused-selector-ternary/expected.svelte
similarity index 100%
rename from test/css/samples/unused-selector-ternary/expected.html
rename to test/css/samples/unused-selector-ternary/expected.svelte
diff --git a/test/css/samples/unused-selector-ternary/input.html b/test/css/samples/unused-selector-ternary/input.svelte
similarity index 100%
rename from test/css/samples/unused-selector-ternary/input.html
rename to test/css/samples/unused-selector-ternary/input.svelte
diff --git a/test/css/samples/unused-selector/expected.html b/test/css/samples/unused-selector/expected.svelte
similarity index 100%
rename from test/css/samples/unused-selector/expected.html
rename to test/css/samples/unused-selector/expected.svelte
diff --git a/test/css/samples/unused-selector/input.html b/test/css/samples/unused-selector/input.svelte
similarity index 100%
rename from test/css/samples/unused-selector/input.html
rename to test/css/samples/unused-selector/input.svelte
diff --git a/test/custom-elements/samples/custom-method/main.html b/test/custom-elements/samples/custom-method/main.svelte
similarity index 100%
rename from test/custom-elements/samples/custom-method/main.html
rename to test/custom-elements/samples/custom-method/main.svelte
diff --git a/test/custom-elements/samples/escaped-css/main.html b/test/custom-elements/samples/escaped-css/main.svelte
similarity index 100%
rename from test/custom-elements/samples/escaped-css/main.html
rename to test/custom-elements/samples/escaped-css/main.svelte
diff --git a/test/custom-elements/samples/html-slots/main.html b/test/custom-elements/samples/html-slots/main.svelte
similarity index 100%
rename from test/custom-elements/samples/html-slots/main.html
rename to test/custom-elements/samples/html-slots/main.svelte
diff --git a/test/custom-elements/samples/html/main.html b/test/custom-elements/samples/html/main.svelte
similarity index 100%
rename from test/custom-elements/samples/html/main.html
rename to test/custom-elements/samples/html/main.svelte
diff --git a/test/custom-elements/samples/nested.skip/Counter.html b/test/custom-elements/samples/nested.skip/Counter.svelte
similarity index 100%
rename from test/custom-elements/samples/nested.skip/Counter.html
rename to test/custom-elements/samples/nested.skip/Counter.svelte
diff --git a/test/custom-elements/samples/nested.skip/main.html b/test/custom-elements/samples/nested.skip/main.svelte
similarity index 75%
rename from test/custom-elements/samples/nested.skip/main.html
rename to test/custom-elements/samples/nested.skip/main.svelte
index 90459c83eb..cb26008061 100644
--- a/test/custom-elements/samples/nested.skip/main.html
+++ b/test/custom-elements/samples/nested.skip/main.svelte
@@ -1,7 +1,7 @@
 <svelte:options tag="my-app"/>
 
 <script>
-	import Counter from './Counter.html';
+	import Counter from './Counter.svelte';
 
 	export let count;
 </script>
diff --git a/test/custom-elements/samples/new-styled/main.html b/test/custom-elements/samples/new-styled/main.svelte
similarity index 100%
rename from test/custom-elements/samples/new-styled/main.html
rename to test/custom-elements/samples/new-styled/main.svelte
diff --git a/test/custom-elements/samples/new/main.html b/test/custom-elements/samples/new/main.svelte
similarity index 100%
rename from test/custom-elements/samples/new/main.html
rename to test/custom-elements/samples/new/main.svelte
diff --git a/test/custom-elements/samples/no-missing-prop-warnings/main.html b/test/custom-elements/samples/no-missing-prop-warnings/main.svelte
similarity index 100%
rename from test/custom-elements/samples/no-missing-prop-warnings/main.html
rename to test/custom-elements/samples/no-missing-prop-warnings/main.svelte
diff --git a/test/custom-elements/samples/oncreate/main.html b/test/custom-elements/samples/oncreate/main.svelte
similarity index 100%
rename from test/custom-elements/samples/oncreate/main.html
rename to test/custom-elements/samples/oncreate/main.svelte
diff --git a/test/custom-elements/samples/props/main.html b/test/custom-elements/samples/props/main.svelte
similarity index 81%
rename from test/custom-elements/samples/props/main.html
rename to test/custom-elements/samples/props/main.svelte
index b36c7f3e3d..80b483bf6e 100644
--- a/test/custom-elements/samples/props/main.html
+++ b/test/custom-elements/samples/props/main.svelte
@@ -1,7 +1,7 @@
 <svelte:options tag="custom-element"/>
 
 <script>
-	import './my-widget.html';
+	import './my-widget.svelte';
 
 	export let items = ['a', 'b', 'c'];
 </script>
diff --git a/test/custom-elements/samples/props/my-widget.html b/test/custom-elements/samples/props/my-widget.svelte
similarity index 100%
rename from test/custom-elements/samples/props/my-widget.html
rename to test/custom-elements/samples/props/my-widget.svelte
diff --git a/test/hydration/samples/basic/_after.html b/test/hydration/samples/basic/_after.svelte
similarity index 100%
rename from test/hydration/samples/basic/_after.html
rename to test/hydration/samples/basic/_after.svelte
diff --git a/test/hydration/samples/basic/_before.html b/test/hydration/samples/basic/_before.svelte
similarity index 100%
rename from test/hydration/samples/basic/_before.html
rename to test/hydration/samples/basic/_before.svelte
diff --git a/test/hydration/samples/basic/main.html b/test/hydration/samples/basic/main.svelte
similarity index 100%
rename from test/hydration/samples/basic/main.html
rename to test/hydration/samples/basic/main.svelte
diff --git a/test/hydration/samples/binding-input/_after.html b/test/hydration/samples/binding-input/_after.svelte
similarity index 100%
rename from test/hydration/samples/binding-input/_after.html
rename to test/hydration/samples/binding-input/_after.svelte
diff --git a/test/hydration/samples/binding-input/_before.html b/test/hydration/samples/binding-input/_before.svelte
similarity index 100%
rename from test/hydration/samples/binding-input/_before.html
rename to test/hydration/samples/binding-input/_before.svelte
diff --git a/test/hydration/samples/binding-input/main.html b/test/hydration/samples/binding-input/main.svelte
similarity index 100%
rename from test/hydration/samples/binding-input/main.html
rename to test/hydration/samples/binding-input/main.svelte
diff --git a/test/hydration/samples/component-in-element/Nested.html b/test/hydration/samples/component-in-element/Nested.svelte
similarity index 100%
rename from test/hydration/samples/component-in-element/Nested.html
rename to test/hydration/samples/component-in-element/Nested.svelte
diff --git a/test/hydration/samples/component-in-element/_after.html b/test/hydration/samples/component-in-element/_after.svelte
similarity index 100%
rename from test/hydration/samples/component-in-element/_after.html
rename to test/hydration/samples/component-in-element/_after.svelte
diff --git a/test/hydration/samples/component-in-element/_before.html b/test/hydration/samples/component-in-element/_before.svelte
similarity index 100%
rename from test/hydration/samples/component-in-element/_before.html
rename to test/hydration/samples/component-in-element/_before.svelte
diff --git a/test/hydration/samples/component-in-element/main.html b/test/hydration/samples/component-in-element/main.html
deleted file mode 100644
index 4367a831ea..0000000000
--- a/test/hydration/samples/component-in-element/main.html
+++ /dev/null
@@ -1,7 +0,0 @@
-<script>
-	import Nested from './Nested.html';
-</script>
-
-<div>
-	<Nested/>
-</div>
\ No newline at end of file
diff --git a/test/hydration/samples/component-in-element/main.svelte b/test/hydration/samples/component-in-element/main.svelte
new file mode 100644
index 0000000000..f1d903fcd6
--- /dev/null
+++ b/test/hydration/samples/component-in-element/main.svelte
@@ -0,0 +1,7 @@
+<script>
+	import Nested from './Nested.svelte';
+</script>
+
+<div>
+	<Nested/>
+</div>
\ No newline at end of file
diff --git a/test/hydration/samples/component/Nested.html b/test/hydration/samples/component/Nested.svelte
similarity index 100%
rename from test/hydration/samples/component/Nested.html
rename to test/hydration/samples/component/Nested.svelte
diff --git a/test/hydration/samples/component/_after.html b/test/hydration/samples/component/_after.svelte
similarity index 100%
rename from test/hydration/samples/component/_after.html
rename to test/hydration/samples/component/_after.svelte
diff --git a/test/hydration/samples/component/_before.html b/test/hydration/samples/component/_before.svelte
similarity index 100%
rename from test/hydration/samples/component/_before.html
rename to test/hydration/samples/component/_before.svelte
diff --git a/test/hydration/samples/component/main.html b/test/hydration/samples/component/main.html
deleted file mode 100644
index 583835f46a..0000000000
--- a/test/hydration/samples/component/main.html
+++ /dev/null
@@ -1,5 +0,0 @@
-<script>
-	import Nested from './Nested.html';
-</script>
-
-<Nested/>
\ No newline at end of file
diff --git a/test/hydration/samples/component/main.svelte b/test/hydration/samples/component/main.svelte
new file mode 100644
index 0000000000..469c37f719
--- /dev/null
+++ b/test/hydration/samples/component/main.svelte
@@ -0,0 +1,5 @@
+<script>
+	import Nested from './Nested.svelte';
+</script>
+
+<Nested/>
\ No newline at end of file
diff --git a/test/hydration/samples/dynamic-text-changed/_after.html b/test/hydration/samples/dynamic-text-changed/_after.svelte
similarity index 100%
rename from test/hydration/samples/dynamic-text-changed/_after.html
rename to test/hydration/samples/dynamic-text-changed/_after.svelte
diff --git a/test/hydration/samples/dynamic-text-changed/_before.html b/test/hydration/samples/dynamic-text-changed/_before.svelte
similarity index 100%
rename from test/hydration/samples/dynamic-text-changed/_before.html
rename to test/hydration/samples/dynamic-text-changed/_before.svelte
diff --git a/test/hydration/samples/dynamic-text-changed/main.html b/test/hydration/samples/dynamic-text-changed/main.svelte
similarity index 100%
rename from test/hydration/samples/dynamic-text-changed/main.html
rename to test/hydration/samples/dynamic-text-changed/main.svelte
diff --git a/test/hydration/samples/dynamic-text/_after.html b/test/hydration/samples/dynamic-text/_after.svelte
similarity index 100%
rename from test/hydration/samples/dynamic-text/_after.html
rename to test/hydration/samples/dynamic-text/_after.svelte
diff --git a/test/hydration/samples/dynamic-text/_before.html b/test/hydration/samples/dynamic-text/_before.svelte
similarity index 100%
rename from test/hydration/samples/dynamic-text/_before.html
rename to test/hydration/samples/dynamic-text/_before.svelte
diff --git a/test/hydration/samples/dynamic-text/main.html b/test/hydration/samples/dynamic-text/main.svelte
similarity index 100%
rename from test/hydration/samples/dynamic-text/main.html
rename to test/hydration/samples/dynamic-text/main.svelte
diff --git a/test/hydration/samples/each-block-arg-clash/_after.html b/test/hydration/samples/each-block-arg-clash/_after.svelte
similarity index 100%
rename from test/hydration/samples/each-block-arg-clash/_after.html
rename to test/hydration/samples/each-block-arg-clash/_after.svelte
diff --git a/test/hydration/samples/each-block-arg-clash/_before.html b/test/hydration/samples/each-block-arg-clash/_before.svelte
similarity index 100%
rename from test/hydration/samples/each-block-arg-clash/_before.html
rename to test/hydration/samples/each-block-arg-clash/_before.svelte
diff --git a/test/hydration/samples/each-block-arg-clash/main.html b/test/hydration/samples/each-block-arg-clash/main.svelte
similarity index 100%
rename from test/hydration/samples/each-block-arg-clash/main.html
rename to test/hydration/samples/each-block-arg-clash/main.svelte
diff --git a/test/hydration/samples/each-block/_after.html b/test/hydration/samples/each-block/_after.svelte
similarity index 100%
rename from test/hydration/samples/each-block/_after.html
rename to test/hydration/samples/each-block/_after.svelte
diff --git a/test/hydration/samples/each-block/_before.html b/test/hydration/samples/each-block/_before.svelte
similarity index 100%
rename from test/hydration/samples/each-block/_before.html
rename to test/hydration/samples/each-block/_before.svelte
diff --git a/test/hydration/samples/each-block/main.html b/test/hydration/samples/each-block/main.svelte
similarity index 100%
rename from test/hydration/samples/each-block/main.html
rename to test/hydration/samples/each-block/main.svelte
diff --git a/test/hydration/samples/element-attribute-added/_after.html b/test/hydration/samples/element-attribute-added/_after.svelte
similarity index 100%
rename from test/hydration/samples/element-attribute-added/_after.html
rename to test/hydration/samples/element-attribute-added/_after.svelte
diff --git a/test/hydration/samples/element-attribute-added/_before.html b/test/hydration/samples/element-attribute-added/_before.svelte
similarity index 100%
rename from test/hydration/samples/element-attribute-added/_before.html
rename to test/hydration/samples/element-attribute-added/_before.svelte
diff --git a/test/hydration/samples/element-attribute-added/main.html b/test/hydration/samples/element-attribute-added/main.svelte
similarity index 100%
rename from test/hydration/samples/element-attribute-added/main.html
rename to test/hydration/samples/element-attribute-added/main.svelte
diff --git a/test/hydration/samples/element-attribute-changed/_after.html b/test/hydration/samples/element-attribute-changed/_after.svelte
similarity index 100%
rename from test/hydration/samples/element-attribute-changed/_after.html
rename to test/hydration/samples/element-attribute-changed/_after.svelte
diff --git a/test/hydration/samples/element-attribute-changed/_before.html b/test/hydration/samples/element-attribute-changed/_before.svelte
similarity index 100%
rename from test/hydration/samples/element-attribute-changed/_before.html
rename to test/hydration/samples/element-attribute-changed/_before.svelte
diff --git a/test/hydration/samples/element-attribute-changed/main.html b/test/hydration/samples/element-attribute-changed/main.svelte
similarity index 100%
rename from test/hydration/samples/element-attribute-changed/main.html
rename to test/hydration/samples/element-attribute-changed/main.svelte
diff --git a/test/hydration/samples/element-attribute-removed/_after.html b/test/hydration/samples/element-attribute-removed/_after.svelte
similarity index 100%
rename from test/hydration/samples/element-attribute-removed/_after.html
rename to test/hydration/samples/element-attribute-removed/_after.svelte
diff --git a/test/hydration/samples/element-attribute-removed/_before.html b/test/hydration/samples/element-attribute-removed/_before.svelte
similarity index 100%
rename from test/hydration/samples/element-attribute-removed/_before.html
rename to test/hydration/samples/element-attribute-removed/_before.svelte
diff --git a/test/hydration/samples/element-attribute-removed/main.html b/test/hydration/samples/element-attribute-removed/main.svelte
similarity index 100%
rename from test/hydration/samples/element-attribute-removed/main.html
rename to test/hydration/samples/element-attribute-removed/main.svelte
diff --git a/test/hydration/samples/element-attribute-unchanged/_after.html b/test/hydration/samples/element-attribute-unchanged/_after.svelte
similarity index 100%
rename from test/hydration/samples/element-attribute-unchanged/_after.html
rename to test/hydration/samples/element-attribute-unchanged/_after.svelte
diff --git a/test/hydration/samples/element-attribute-unchanged/_before.html b/test/hydration/samples/element-attribute-unchanged/_before.svelte
similarity index 100%
rename from test/hydration/samples/element-attribute-unchanged/_before.html
rename to test/hydration/samples/element-attribute-unchanged/_before.svelte
diff --git a/test/hydration/samples/element-attribute-unchanged/main.html b/test/hydration/samples/element-attribute-unchanged/main.svelte
similarity index 100%
rename from test/hydration/samples/element-attribute-unchanged/main.html
rename to test/hydration/samples/element-attribute-unchanged/main.svelte
diff --git a/test/hydration/samples/element-nested/_after.html b/test/hydration/samples/element-nested/_after.svelte
similarity index 100%
rename from test/hydration/samples/element-nested/_after.html
rename to test/hydration/samples/element-nested/_after.svelte
diff --git a/test/hydration/samples/element-nested/_before.html b/test/hydration/samples/element-nested/_before.svelte
similarity index 100%
rename from test/hydration/samples/element-nested/_before.html
rename to test/hydration/samples/element-nested/_before.svelte
diff --git a/test/hydration/samples/element-nested/main.html b/test/hydration/samples/element-nested/main.svelte
similarity index 100%
rename from test/hydration/samples/element-nested/main.html
rename to test/hydration/samples/element-nested/main.svelte
diff --git a/test/hydration/samples/element-ref/_after.html b/test/hydration/samples/element-ref/_after.svelte
similarity index 100%
rename from test/hydration/samples/element-ref/_after.html
rename to test/hydration/samples/element-ref/_after.svelte
diff --git a/test/hydration/samples/element-ref/_before.html b/test/hydration/samples/element-ref/_before.svelte
similarity index 100%
rename from test/hydration/samples/element-ref/_before.html
rename to test/hydration/samples/element-ref/_before.svelte
diff --git a/test/hydration/samples/element-ref/main.html b/test/hydration/samples/element-ref/main.svelte
similarity index 100%
rename from test/hydration/samples/element-ref/main.html
rename to test/hydration/samples/element-ref/main.svelte
diff --git a/test/hydration/samples/event-handler/_after.html b/test/hydration/samples/event-handler/_after.svelte
similarity index 100%
rename from test/hydration/samples/event-handler/_after.html
rename to test/hydration/samples/event-handler/_after.svelte
diff --git a/test/hydration/samples/event-handler/_before.html b/test/hydration/samples/event-handler/_before.svelte
similarity index 100%
rename from test/hydration/samples/event-handler/_before.html
rename to test/hydration/samples/event-handler/_before.svelte
diff --git a/test/hydration/samples/event-handler/main.html b/test/hydration/samples/event-handler/main.svelte
similarity index 100%
rename from test/hydration/samples/event-handler/main.html
rename to test/hydration/samples/event-handler/main.svelte
diff --git a/test/hydration/samples/if-block-anchor/_after.html b/test/hydration/samples/if-block-anchor/_after.svelte
similarity index 100%
rename from test/hydration/samples/if-block-anchor/_after.html
rename to test/hydration/samples/if-block-anchor/_after.svelte
diff --git a/test/hydration/samples/if-block-anchor/_before.html b/test/hydration/samples/if-block-anchor/_before.svelte
similarity index 100%
rename from test/hydration/samples/if-block-anchor/_before.html
rename to test/hydration/samples/if-block-anchor/_before.svelte
diff --git a/test/hydration/samples/if-block-anchor/main.html b/test/hydration/samples/if-block-anchor/main.svelte
similarity index 100%
rename from test/hydration/samples/if-block-anchor/main.html
rename to test/hydration/samples/if-block-anchor/main.svelte
diff --git a/test/hydration/samples/if-block-false/_after.html b/test/hydration/samples/if-block-false/_after.svelte
similarity index 100%
rename from test/hydration/samples/if-block-false/_after.html
rename to test/hydration/samples/if-block-false/_after.svelte
diff --git a/test/hydration/samples/if-block-false/_before.html b/test/hydration/samples/if-block-false/_before.svelte
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rename from test/hydration/samples/if-block-false/_before.html
rename to test/hydration/samples/if-block-false/_before.svelte
diff --git a/test/hydration/samples/if-block-false/main.html b/test/hydration/samples/if-block-false/main.svelte
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rename from test/hydration/samples/if-block-false/main.html
rename to test/hydration/samples/if-block-false/main.svelte
diff --git a/test/hydration/samples/if-block-update/_after.html b/test/hydration/samples/if-block-update/_after.svelte
similarity index 100%
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-<script>
-	import LazyLoad from './LazyLoad.html';
-</script>
-
-<LazyLoad load="{() => import('./Foo.html')}"/>
\ No newline at end of file
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+<script>
+	import LazyLoad from './LazyLoad.svelte';
+</script>
+
+<LazyLoad load="{() => import('./Foo.svelte')}"/>
\ No newline at end of file
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-<script>
-	import Imported from 'Imported.html';
-</script>
-
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\ No newline at end of file
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index 0000000000..fb2054bc7f
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+<script>
+	import Imported from 'Imported.svelte';
+</script>
+
+<Imported/>
+<NonImported/>
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rename from test/runtime/samples/action-this/main.html
rename to test/runtime/samples/action-this/main.svelte
diff --git a/test/runtime/samples/action-update/main.html b/test/runtime/samples/action-update/main.svelte
similarity index 100%
rename from test/runtime/samples/action-update/main.html
rename to test/runtime/samples/action-update/main.svelte
diff --git a/test/runtime/samples/action/main.html b/test/runtime/samples/action/main.svelte
similarity index 100%
rename from test/runtime/samples/action/main.html
rename to test/runtime/samples/action/main.svelte
diff --git a/test/runtime/samples/after-render-prevents-loop/main.html b/test/runtime/samples/after-render-prevents-loop/main.svelte
similarity index 100%
rename from test/runtime/samples/after-render-prevents-loop/main.html
rename to test/runtime/samples/after-render-prevents-loop/main.svelte
diff --git a/test/runtime/samples/after-render-triggers-update/main.html b/test/runtime/samples/after-render-triggers-update/main.svelte
similarity index 100%
rename from test/runtime/samples/after-render-triggers-update/main.html
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diff --git a/test/runtime/samples/animation-css/main.html b/test/runtime/samples/animation-css/main.svelte
similarity index 100%
rename from test/runtime/samples/animation-css/main.html
rename to test/runtime/samples/animation-css/main.svelte
diff --git a/test/runtime/samples/animation-js-delay/main.html b/test/runtime/samples/animation-js-delay/main.svelte
similarity index 100%
rename from test/runtime/samples/animation-js-delay/main.html
rename to test/runtime/samples/animation-js-delay/main.svelte
diff --git a/test/runtime/samples/animation-js-easing/main.html b/test/runtime/samples/animation-js-easing/main.svelte
similarity index 100%
rename from test/runtime/samples/animation-js-easing/main.html
rename to test/runtime/samples/animation-js-easing/main.svelte
diff --git a/test/runtime/samples/animation-js/main.html b/test/runtime/samples/animation-js/main.svelte
similarity index 100%
rename from test/runtime/samples/animation-js/main.html
rename to test/runtime/samples/animation-js/main.svelte
diff --git a/test/runtime/samples/assignment-in-init/main.html b/test/runtime/samples/assignment-in-init/main.svelte
similarity index 100%
rename from test/runtime/samples/assignment-in-init/main.html
rename to test/runtime/samples/assignment-in-init/main.svelte
diff --git a/test/runtime/samples/assignment-to-computed-property/main.html b/test/runtime/samples/assignment-to-computed-property/main.svelte
similarity index 100%
rename from test/runtime/samples/assignment-to-computed-property/main.html
rename to test/runtime/samples/assignment-to-computed-property/main.svelte
diff --git a/test/runtime/samples/attribute-boolean-false/main.html b/test/runtime/samples/attribute-boolean-false/main.svelte
similarity index 100%
rename from test/runtime/samples/attribute-boolean-false/main.html
rename to test/runtime/samples/attribute-boolean-false/main.svelte
diff --git a/test/runtime/samples/attribute-boolean-indeterminate/main.html b/test/runtime/samples/attribute-boolean-indeterminate/main.svelte
similarity index 100%
rename from test/runtime/samples/attribute-boolean-indeterminate/main.html
rename to test/runtime/samples/attribute-boolean-indeterminate/main.svelte
diff --git a/test/runtime/samples/attribute-boolean-true/main.html b/test/runtime/samples/attribute-boolean-true/main.svelte
similarity index 100%
rename from test/runtime/samples/attribute-boolean-true/main.html
rename to test/runtime/samples/attribute-boolean-true/main.svelte
diff --git a/test/runtime/samples/attribute-casing/main.html b/test/runtime/samples/attribute-casing/main.svelte
similarity index 100%
rename from test/runtime/samples/attribute-casing/main.html
rename to test/runtime/samples/attribute-casing/main.svelte
diff --git a/test/runtime/samples/attribute-dynamic-multiple/main.html b/test/runtime/samples/attribute-dynamic-multiple/main.svelte
similarity index 100%
rename from test/runtime/samples/attribute-dynamic-multiple/main.html
rename to test/runtime/samples/attribute-dynamic-multiple/main.svelte
diff --git a/test/runtime/samples/attribute-dynamic-no-dependencies/main.html b/test/runtime/samples/attribute-dynamic-no-dependencies/main.svelte
similarity index 100%
rename from test/runtime/samples/attribute-dynamic-no-dependencies/main.html
rename to test/runtime/samples/attribute-dynamic-no-dependencies/main.svelte
diff --git a/test/runtime/samples/attribute-dynamic-quotemarks/main.html b/test/runtime/samples/attribute-dynamic-quotemarks/main.svelte
similarity index 100%
rename from test/runtime/samples/attribute-dynamic-quotemarks/main.html
rename to test/runtime/samples/attribute-dynamic-quotemarks/main.svelte
diff --git a/test/runtime/samples/attribute-dynamic-shorthand/main.html b/test/runtime/samples/attribute-dynamic-shorthand/main.svelte
similarity index 100%
rename from test/runtime/samples/attribute-dynamic-shorthand/main.html
rename to test/runtime/samples/attribute-dynamic-shorthand/main.svelte
diff --git a/test/runtime/samples/attribute-dynamic-type/main.html b/test/runtime/samples/attribute-dynamic-type/main.svelte
similarity index 100%
rename from test/runtime/samples/attribute-dynamic-type/main.html
rename to test/runtime/samples/attribute-dynamic-type/main.svelte
diff --git a/test/runtime/samples/attribute-dynamic/main.html b/test/runtime/samples/attribute-dynamic/main.svelte
similarity index 100%
rename from test/runtime/samples/attribute-dynamic/main.html
rename to test/runtime/samples/attribute-dynamic/main.svelte
diff --git a/test/runtime/samples/attribute-empty-svg/main.html b/test/runtime/samples/attribute-empty-svg/main.svelte
similarity index 100%
rename from test/runtime/samples/attribute-empty-svg/main.html
rename to test/runtime/samples/attribute-empty-svg/main.svelte
diff --git a/test/runtime/samples/attribute-empty/main.html b/test/runtime/samples/attribute-empty/main.svelte
similarity index 100%
rename from test/runtime/samples/attribute-empty/main.html
rename to test/runtime/samples/attribute-empty/main.svelte
diff --git a/test/runtime/samples/attribute-namespaced/main.html b/test/runtime/samples/attribute-namespaced/main.svelte
similarity index 100%
rename from test/runtime/samples/attribute-namespaced/main.html
rename to test/runtime/samples/attribute-namespaced/main.svelte
diff --git a/test/runtime/samples/attribute-partial-number/Component.html b/test/runtime/samples/attribute-partial-number/Component.svelte
similarity index 100%
rename from test/runtime/samples/attribute-partial-number/Component.html
rename to test/runtime/samples/attribute-partial-number/Component.svelte
diff --git a/test/runtime/samples/attribute-partial-number/main.html b/test/runtime/samples/attribute-partial-number/main.html
deleted file mode 100644
index c720ea4eed..0000000000
--- a/test/runtime/samples/attribute-partial-number/main.html
+++ /dev/null
@@ -1,5 +0,0 @@
-<script>
-	import Component from './Component.html';
-</script>
-
-<Component value="10px"/>
\ No newline at end of file
diff --git a/test/runtime/samples/attribute-partial-number/main.svelte b/test/runtime/samples/attribute-partial-number/main.svelte
new file mode 100644
index 0000000000..163116e4fa
--- /dev/null
+++ b/test/runtime/samples/attribute-partial-number/main.svelte
@@ -0,0 +1,5 @@
+<script>
+	import Component from './Component.svelte';
+</script>
+
+<Component value="10px"/>
\ No newline at end of file
diff --git a/test/runtime/samples/attribute-prefer-expression/main.html b/test/runtime/samples/attribute-prefer-expression/main.svelte
similarity index 100%
rename from test/runtime/samples/attribute-prefer-expression/main.html
rename to test/runtime/samples/attribute-prefer-expression/main.svelte
diff --git a/test/runtime/samples/attribute-static-at-symbol/main.html b/test/runtime/samples/attribute-static-at-symbol/main.svelte
similarity index 100%
rename from test/runtime/samples/attribute-static-at-symbol/main.html
rename to test/runtime/samples/attribute-static-at-symbol/main.svelte
diff --git a/test/runtime/samples/attribute-static-boolean/main.html b/test/runtime/samples/attribute-static-boolean/main.svelte
similarity index 100%
rename from test/runtime/samples/attribute-static-boolean/main.html
rename to test/runtime/samples/attribute-static-boolean/main.svelte
diff --git a/test/runtime/samples/attribute-static-quotemarks/main.html b/test/runtime/samples/attribute-static-quotemarks/main.svelte
similarity index 100%
rename from test/runtime/samples/attribute-static-quotemarks/main.html
rename to test/runtime/samples/attribute-static-quotemarks/main.svelte
diff --git a/test/runtime/samples/attribute-static/main.html b/test/runtime/samples/attribute-static/main.svelte
similarity index 100%
rename from test/runtime/samples/attribute-static/main.html
rename to test/runtime/samples/attribute-static/main.svelte
diff --git a/test/runtime/samples/attribute-unknown-without-value/main.html b/test/runtime/samples/attribute-unknown-without-value/main.svelte
similarity index 100%
rename from test/runtime/samples/attribute-unknown-without-value/main.html
rename to test/runtime/samples/attribute-unknown-without-value/main.svelte
diff --git a/test/runtime/samples/autofocus/main.html b/test/runtime/samples/autofocus/main.svelte
similarity index 100%
rename from test/runtime/samples/autofocus/main.html
rename to test/runtime/samples/autofocus/main.svelte
diff --git a/test/runtime/samples/await-component-oncreate/Foo.html b/test/runtime/samples/await-component-oncreate/Foo.svelte
similarity index 100%
rename from test/runtime/samples/await-component-oncreate/Foo.html
rename to test/runtime/samples/await-component-oncreate/Foo.svelte
diff --git a/test/runtime/samples/await-component-oncreate/main.html b/test/runtime/samples/await-component-oncreate/main.svelte
similarity index 67%
rename from test/runtime/samples/await-component-oncreate/main.html
rename to test/runtime/samples/await-component-oncreate/main.svelte
index 80a686962e..d1ddc16fd2 100644
--- a/test/runtime/samples/await-component-oncreate/main.html
+++ b/test/runtime/samples/await-component-oncreate/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Foo from './Foo.html';
+	import Foo from './Foo.svelte';
 
 	export let promise;
 </script>
diff --git a/test/runtime/samples/await-containing-if/main.html b/test/runtime/samples/await-containing-if/main.svelte
similarity index 100%
rename from test/runtime/samples/await-containing-if/main.html
rename to test/runtime/samples/await-containing-if/main.svelte
diff --git a/test/runtime/samples/await-in-each/main.html b/test/runtime/samples/await-in-each/main.svelte
similarity index 100%
rename from test/runtime/samples/await-in-each/main.html
rename to test/runtime/samples/await-in-each/main.svelte
diff --git a/test/runtime/samples/await-set-simultaneous/main.html b/test/runtime/samples/await-set-simultaneous/main.svelte
similarity index 100%
rename from test/runtime/samples/await-set-simultaneous/main.html
rename to test/runtime/samples/await-set-simultaneous/main.svelte
diff --git a/test/runtime/samples/await-then-catch-anchor/main.html b/test/runtime/samples/await-then-catch-anchor/main.svelte
similarity index 100%
rename from test/runtime/samples/await-then-catch-anchor/main.html
rename to test/runtime/samples/await-then-catch-anchor/main.svelte
diff --git a/test/runtime/samples/await-then-catch-event/main.html b/test/runtime/samples/await-then-catch-event/main.svelte
similarity index 100%
rename from test/runtime/samples/await-then-catch-event/main.html
rename to test/runtime/samples/await-then-catch-event/main.svelte
diff --git a/test/runtime/samples/await-then-catch-if/main.html b/test/runtime/samples/await-then-catch-if/main.svelte
similarity index 100%
rename from test/runtime/samples/await-then-catch-if/main.html
rename to test/runtime/samples/await-then-catch-if/main.svelte
diff --git a/test/runtime/samples/await-then-catch-in-slot/Foo.html b/test/runtime/samples/await-then-catch-in-slot/Foo.svelte
similarity index 100%
rename from test/runtime/samples/await-then-catch-in-slot/Foo.html
rename to test/runtime/samples/await-then-catch-in-slot/Foo.svelte
diff --git a/test/runtime/samples/await-then-catch-in-slot/main.html b/test/runtime/samples/await-then-catch-in-slot/main.svelte
similarity index 84%
rename from test/runtime/samples/await-then-catch-in-slot/main.html
rename to test/runtime/samples/await-then-catch-in-slot/main.svelte
index ded116356c..3aa75374ea 100644
--- a/test/runtime/samples/await-then-catch-in-slot/main.html
+++ b/test/runtime/samples/await-then-catch-in-slot/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Foo from './Foo.html';
+	import Foo from './Foo.svelte';
 
 	export let thePromise;
 </script>
diff --git a/test/runtime/samples/await-then-catch-multiple/main.html b/test/runtime/samples/await-then-catch-multiple/main.svelte
similarity index 100%
rename from test/runtime/samples/await-then-catch-multiple/main.html
rename to test/runtime/samples/await-then-catch-multiple/main.svelte
diff --git a/test/runtime/samples/await-then-catch-no-values/main.html b/test/runtime/samples/await-then-catch-no-values/main.svelte
similarity index 100%
rename from test/runtime/samples/await-then-catch-no-values/main.html
rename to test/runtime/samples/await-then-catch-no-values/main.svelte
diff --git a/test/runtime/samples/await-then-catch-non-promise/main.html b/test/runtime/samples/await-then-catch-non-promise/main.svelte
similarity index 100%
rename from test/runtime/samples/await-then-catch-non-promise/main.html
rename to test/runtime/samples/await-then-catch-non-promise/main.svelte
diff --git a/test/runtime/samples/await-then-catch-order/main.html b/test/runtime/samples/await-then-catch-order/main.svelte
similarity index 100%
rename from test/runtime/samples/await-then-catch-order/main.html
rename to test/runtime/samples/await-then-catch-order/main.svelte
diff --git a/test/runtime/samples/await-then-catch-static/main.html b/test/runtime/samples/await-then-catch-static/main.svelte
similarity index 100%
rename from test/runtime/samples/await-then-catch-static/main.html
rename to test/runtime/samples/await-then-catch-static/main.svelte
diff --git a/test/runtime/samples/await-then-catch/main.html b/test/runtime/samples/await-then-catch/main.svelte
similarity index 100%
rename from test/runtime/samples/await-then-catch/main.html
rename to test/runtime/samples/await-then-catch/main.svelte
diff --git a/test/runtime/samples/await-then-shorthand/main.html b/test/runtime/samples/await-then-shorthand/main.svelte
similarity index 100%
rename from test/runtime/samples/await-then-shorthand/main.html
rename to test/runtime/samples/await-then-shorthand/main.svelte
diff --git a/test/runtime/samples/await-with-components/Widget.html b/test/runtime/samples/await-with-components/Widget.svelte
similarity index 100%
rename from test/runtime/samples/await-with-components/Widget.html
rename to test/runtime/samples/await-with-components/Widget.svelte
diff --git a/test/runtime/samples/await-with-components/main.html b/test/runtime/samples/await-with-components/main.svelte
similarity index 78%
rename from test/runtime/samples/await-with-components/main.html
rename to test/runtime/samples/await-with-components/main.svelte
index 84894997e1..02b32bb496 100644
--- a/test/runtime/samples/await-with-components/main.html
+++ b/test/runtime/samples/await-with-components/main.svelte
@@ -7,6 +7,6 @@
 {/await}
 
 <script>
-	import Widget from './Widget.html';
+	import Widget from './Widget.svelte';
 	export let promise = Promise.resolve();
 </script>
\ No newline at end of file
diff --git a/test/runtime/samples/before-render-chain/Item.html b/test/runtime/samples/before-render-chain/Item.svelte
similarity index 100%
rename from test/runtime/samples/before-render-chain/Item.html
rename to test/runtime/samples/before-render-chain/Item.svelte
diff --git a/test/runtime/samples/before-render-chain/List.html b/test/runtime/samples/before-render-chain/List.svelte
similarity index 82%
rename from test/runtime/samples/before-render-chain/List.html
rename to test/runtime/samples/before-render-chain/List.svelte
index 645356bd92..5b12d8a104 100644
--- a/test/runtime/samples/before-render-chain/List.html
+++ b/test/runtime/samples/before-render-chain/List.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Item from './Item.html';
+	import Item from './Item.svelte';
 
 	export let items = [3, 2, 1];
 
diff --git a/test/runtime/samples/before-render-chain/main.html b/test/runtime/samples/before-render-chain/main.svelte
similarity index 64%
rename from test/runtime/samples/before-render-chain/main.html
rename to test/runtime/samples/before-render-chain/main.svelte
index e194fe786a..4f6e432aa8 100644
--- a/test/runtime/samples/before-render-chain/main.html
+++ b/test/runtime/samples/before-render-chain/main.svelte
@@ -1,7 +1,7 @@
 <script>
 	export let list;
 
-	import List from './List.html';
+	import List from './List.svelte';
 </script>
 
 <List bind:this={list}/>
diff --git a/test/runtime/samples/before-render-prevents-loop/main.html b/test/runtime/samples/before-render-prevents-loop/main.svelte
similarity index 100%
rename from test/runtime/samples/before-render-prevents-loop/main.html
rename to test/runtime/samples/before-render-prevents-loop/main.svelte
diff --git a/test/runtime/samples/binding-audio-currenttime-duration-volume/main.html b/test/runtime/samples/binding-audio-currenttime-duration-volume/main.svelte
similarity index 100%
rename from test/runtime/samples/binding-audio-currenttime-duration-volume/main.html
rename to test/runtime/samples/binding-audio-currenttime-duration-volume/main.svelte
diff --git a/test/runtime/samples/binding-indirect-computed/main.html b/test/runtime/samples/binding-indirect-computed/main.svelte
similarity index 100%
rename from test/runtime/samples/binding-indirect-computed/main.html
rename to test/runtime/samples/binding-indirect-computed/main.svelte
diff --git a/test/runtime/samples/binding-indirect/main.html b/test/runtime/samples/binding-indirect/main.svelte
similarity index 100%
rename from test/runtime/samples/binding-indirect/main.html
rename to test/runtime/samples/binding-indirect/main.svelte
diff --git a/test/runtime/samples/binding-input-checkbox-deep-contextual/main.html b/test/runtime/samples/binding-input-checkbox-deep-contextual/main.svelte
similarity index 100%
rename from test/runtime/samples/binding-input-checkbox-deep-contextual/main.html
rename to test/runtime/samples/binding-input-checkbox-deep-contextual/main.svelte
diff --git a/test/runtime/samples/binding-input-checkbox-group-outside-each/main.html b/test/runtime/samples/binding-input-checkbox-group-outside-each/main.svelte
similarity index 100%
rename from test/runtime/samples/binding-input-checkbox-group-outside-each/main.html
rename to test/runtime/samples/binding-input-checkbox-group-outside-each/main.svelte
diff --git a/test/runtime/samples/binding-input-checkbox-group/main.html b/test/runtime/samples/binding-input-checkbox-group/main.svelte
similarity index 100%
rename from test/runtime/samples/binding-input-checkbox-group/main.html
rename to test/runtime/samples/binding-input-checkbox-group/main.svelte
diff --git a/test/runtime/samples/binding-input-checkbox-indeterminate/main.html b/test/runtime/samples/binding-input-checkbox-indeterminate/main.svelte
similarity index 100%
rename from test/runtime/samples/binding-input-checkbox-indeterminate/main.html
rename to test/runtime/samples/binding-input-checkbox-indeterminate/main.svelte
diff --git a/test/runtime/samples/binding-input-checkbox-with-event-in-each/main.html b/test/runtime/samples/binding-input-checkbox-with-event-in-each/main.svelte
similarity index 100%
rename from test/runtime/samples/binding-input-checkbox-with-event-in-each/main.html
rename to test/runtime/samples/binding-input-checkbox-with-event-in-each/main.svelte
diff --git a/test/runtime/samples/binding-input-checkbox/main.html b/test/runtime/samples/binding-input-checkbox/main.svelte
similarity index 100%
rename from test/runtime/samples/binding-input-checkbox/main.html
rename to test/runtime/samples/binding-input-checkbox/main.svelte
diff --git a/test/runtime/samples/binding-input-number/main.html b/test/runtime/samples/binding-input-number/main.svelte
similarity index 100%
rename from test/runtime/samples/binding-input-number/main.html
rename to test/runtime/samples/binding-input-number/main.svelte
diff --git a/test/runtime/samples/binding-input-radio-group/main.html b/test/runtime/samples/binding-input-radio-group/main.svelte
similarity index 100%
rename from test/runtime/samples/binding-input-radio-group/main.html
rename to test/runtime/samples/binding-input-radio-group/main.svelte
diff --git a/test/runtime/samples/binding-input-range-change/main.html b/test/runtime/samples/binding-input-range-change/main.svelte
similarity index 100%
rename from test/runtime/samples/binding-input-range-change/main.html
rename to test/runtime/samples/binding-input-range-change/main.svelte
diff --git a/test/runtime/samples/binding-input-range/main.html b/test/runtime/samples/binding-input-range/main.svelte
similarity index 100%
rename from test/runtime/samples/binding-input-range/main.html
rename to test/runtime/samples/binding-input-range/main.svelte
diff --git a/test/runtime/samples/binding-input-text-contextual-deconflicted/main.html b/test/runtime/samples/binding-input-text-contextual-deconflicted/main.svelte
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rename from test/runtime/samples/binding-input-text-contextual-deconflicted/main.html
rename to test/runtime/samples/binding-input-text-contextual-deconflicted/main.svelte
diff --git a/test/runtime/samples/binding-input-text-contextual/main.html b/test/runtime/samples/binding-input-text-contextual/main.svelte
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rename from test/runtime/samples/binding-input-text-contextual/main.html
rename to test/runtime/samples/binding-input-text-contextual/main.svelte
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rename from test/runtime/samples/binding-input-text-deep-computed-dynamic/main.html
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diff --git a/test/runtime/samples/binding-input-text-deep-computed/main.html b/test/runtime/samples/binding-input-text-deep-computed/main.svelte
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rename from test/runtime/samples/binding-input-text-deep-computed/main.html
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diff --git a/test/runtime/samples/binding-input-text-deep-contextual-computed-dynamic/main.html b/test/runtime/samples/binding-input-text-deep-contextual-computed-dynamic/main.svelte
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rename from test/runtime/samples/binding-input-text-deep-contextual-computed-dynamic/main.html
rename to test/runtime/samples/binding-input-text-deep-contextual-computed-dynamic/main.svelte
diff --git a/test/runtime/samples/binding-input-text-deep-contextual/main.html b/test/runtime/samples/binding-input-text-deep-contextual/main.svelte
similarity index 100%
rename from test/runtime/samples/binding-input-text-deep-contextual/main.html
rename to test/runtime/samples/binding-input-text-deep-contextual/main.svelte
diff --git a/test/runtime/samples/binding-input-text-deep/main.html b/test/runtime/samples/binding-input-text-deep/main.svelte
similarity index 100%
rename from test/runtime/samples/binding-input-text-deep/main.html
rename to test/runtime/samples/binding-input-text-deep/main.svelte
diff --git a/test/runtime/samples/binding-input-text/main.html b/test/runtime/samples/binding-input-text/main.svelte
similarity index 100%
rename from test/runtime/samples/binding-input-text/main.html
rename to test/runtime/samples/binding-input-text/main.svelte
diff --git a/test/runtime/samples/binding-input-with-event/main.html b/test/runtime/samples/binding-input-with-event/main.svelte
similarity index 100%
rename from test/runtime/samples/binding-input-with-event/main.html
rename to test/runtime/samples/binding-input-with-event/main.svelte
diff --git a/test/runtime/samples/binding-select-implicit-option-value/main.html b/test/runtime/samples/binding-select-implicit-option-value/main.svelte
similarity index 100%
rename from test/runtime/samples/binding-select-implicit-option-value/main.html
rename to test/runtime/samples/binding-select-implicit-option-value/main.svelte
diff --git a/test/runtime/samples/binding-select-in-each-block/main.html b/test/runtime/samples/binding-select-in-each-block/main.svelte
similarity index 100%
rename from test/runtime/samples/binding-select-in-each-block/main.html
rename to test/runtime/samples/binding-select-in-each-block/main.svelte
diff --git a/test/runtime/samples/binding-select-in-yield/Modal.html b/test/runtime/samples/binding-select-in-yield/Modal.svelte
similarity index 100%
rename from test/runtime/samples/binding-select-in-yield/Modal.html
rename to test/runtime/samples/binding-select-in-yield/Modal.svelte
diff --git a/test/runtime/samples/binding-select-in-yield/main.html b/test/runtime/samples/binding-select-in-yield/main.svelte
similarity index 85%
rename from test/runtime/samples/binding-select-in-yield/main.html
rename to test/runtime/samples/binding-select-in-yield/main.svelte
index cb1499e1c7..2d3ef28f28 100644
--- a/test/runtime/samples/binding-select-in-yield/main.html
+++ b/test/runtime/samples/binding-select-in-yield/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Modal from './Modal.html';
+	import Modal from './Modal.svelte';
 
 	export let modal;
 	export let letter;
diff --git a/test/runtime/samples/binding-select-initial-value-undefined/main.html b/test/runtime/samples/binding-select-initial-value-undefined/main.svelte
similarity index 100%
rename from test/runtime/samples/binding-select-initial-value-undefined/main.html
rename to test/runtime/samples/binding-select-initial-value-undefined/main.svelte
diff --git a/test/runtime/samples/binding-select-initial-value/main.html b/test/runtime/samples/binding-select-initial-value/main.svelte
similarity index 100%
rename from test/runtime/samples/binding-select-initial-value/main.html
rename to test/runtime/samples/binding-select-initial-value/main.svelte
diff --git a/test/runtime/samples/binding-select-late/main.html b/test/runtime/samples/binding-select-late/main.svelte
similarity index 100%
rename from test/runtime/samples/binding-select-late/main.html
rename to test/runtime/samples/binding-select-late/main.svelte
diff --git a/test/runtime/samples/binding-select-multiple/main.html b/test/runtime/samples/binding-select-multiple/main.svelte
similarity index 100%
rename from test/runtime/samples/binding-select-multiple/main.html
rename to test/runtime/samples/binding-select-multiple/main.svelte
diff --git a/test/runtime/samples/binding-select-optgroup/main.html b/test/runtime/samples/binding-select-optgroup/main.svelte
similarity index 100%
rename from test/runtime/samples/binding-select-optgroup/main.html
rename to test/runtime/samples/binding-select-optgroup/main.svelte
diff --git a/test/runtime/samples/binding-select/main.html b/test/runtime/samples/binding-select/main.svelte
similarity index 100%
rename from test/runtime/samples/binding-select/main.html
rename to test/runtime/samples/binding-select/main.svelte
diff --git a/test/runtime/samples/binding-store-deep/main.html b/test/runtime/samples/binding-store-deep/main.svelte
similarity index 100%
rename from test/runtime/samples/binding-store-deep/main.html
rename to test/runtime/samples/binding-store-deep/main.svelte
diff --git a/test/runtime/samples/binding-store/main.html b/test/runtime/samples/binding-store/main.svelte
similarity index 100%
rename from test/runtime/samples/binding-store/main.html
rename to test/runtime/samples/binding-store/main.svelte
diff --git a/test/runtime/samples/binding-textarea/main.html b/test/runtime/samples/binding-textarea/main.svelte
similarity index 100%
rename from test/runtime/samples/binding-textarea/main.html
rename to test/runtime/samples/binding-textarea/main.svelte
diff --git a/test/runtime/samples/binding-this-and-value/main.html b/test/runtime/samples/binding-this-and-value/main.svelte
similarity index 100%
rename from test/runtime/samples/binding-this-and-value/main.html
rename to test/runtime/samples/binding-this-and-value/main.svelte
diff --git a/test/runtime/samples/binding-this-component-reactive/Foo.html b/test/runtime/samples/binding-this-component-reactive/Foo.svelte
similarity index 100%
rename from test/runtime/samples/binding-this-component-reactive/Foo.html
rename to test/runtime/samples/binding-this-component-reactive/Foo.svelte
diff --git a/test/runtime/samples/binding-this-component-reactive/main.html b/test/runtime/samples/binding-this-component-reactive/main.svelte
similarity index 73%
rename from test/runtime/samples/binding-this-component-reactive/main.html
rename to test/runtime/samples/binding-this-component-reactive/main.svelte
index b9a4709bd7..25b134105b 100644
--- a/test/runtime/samples/binding-this-component-reactive/main.html
+++ b/test/runtime/samples/binding-this-component-reactive/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Foo from './Foo.html';
+	import Foo from './Foo.svelte';
 	export let foo;
 </script>
 
diff --git a/test/runtime/samples/binding-this-element-reactive/main.html b/test/runtime/samples/binding-this-element-reactive/main.svelte
similarity index 100%
rename from test/runtime/samples/binding-this-element-reactive/main.html
rename to test/runtime/samples/binding-this-element-reactive/main.svelte
diff --git a/test/runtime/samples/binding-this-no-innerhtml/main.html b/test/runtime/samples/binding-this-no-innerhtml/main.svelte
similarity index 100%
rename from test/runtime/samples/binding-this-no-innerhtml/main.html
rename to test/runtime/samples/binding-this-no-innerhtml/main.svelte
diff --git a/test/runtime/samples/binding-this-unset/main.html b/test/runtime/samples/binding-this-unset/main.svelte
similarity index 100%
rename from test/runtime/samples/binding-this-unset/main.html
rename to test/runtime/samples/binding-this-unset/main.svelte
diff --git a/test/runtime/samples/binding-this-with-context/main.html b/test/runtime/samples/binding-this-with-context/main.svelte
similarity index 100%
rename from test/runtime/samples/binding-this-with-context/main.html
rename to test/runtime/samples/binding-this-with-context/main.svelte
diff --git a/test/runtime/samples/binding-this/main.html b/test/runtime/samples/binding-this/main.svelte
similarity index 100%
rename from test/runtime/samples/binding-this/main.html
rename to test/runtime/samples/binding-this/main.svelte
diff --git a/test/runtime/samples/bindings-before-onmount/One.html b/test/runtime/samples/bindings-before-onmount/One.svelte
similarity index 74%
rename from test/runtime/samples/bindings-before-onmount/One.html
rename to test/runtime/samples/bindings-before-onmount/One.svelte
index b2ba905ec9..5dd38a6f08 100644
--- a/test/runtime/samples/bindings-before-onmount/One.html
+++ b/test/runtime/samples/bindings-before-onmount/One.svelte
@@ -1,6 +1,6 @@
 <script>
 	import { onMount } from 'svelte';
-	import Two from './Two.html';
+	import Two from './Two.svelte';
 
 	export let snapshot;
 	export let foo;
diff --git a/test/runtime/samples/bindings-before-onmount/Two.html b/test/runtime/samples/bindings-before-onmount/Two.svelte
similarity index 100%
rename from test/runtime/samples/bindings-before-onmount/Two.html
rename to test/runtime/samples/bindings-before-onmount/Two.svelte
diff --git a/test/runtime/samples/bindings-before-onmount/main.html b/test/runtime/samples/bindings-before-onmount/main.html
deleted file mode 100644
index efb36a208e..0000000000
--- a/test/runtime/samples/bindings-before-onmount/main.html
+++ /dev/null
@@ -1,7 +0,0 @@
-<script>
-	import One from './One.html';
-
-	export let one;
-</script>
-
-<One bind:this={one}/>
\ No newline at end of file
diff --git a/test/runtime/samples/bindings-before-onmount/main.svelte b/test/runtime/samples/bindings-before-onmount/main.svelte
new file mode 100644
index 0000000000..65c1221b26
--- /dev/null
+++ b/test/runtime/samples/bindings-before-onmount/main.svelte
@@ -0,0 +1,7 @@
+<script>
+	import One from './One.svelte';
+
+	export let one;
+</script>
+
+<One bind:this={one}/>
\ No newline at end of file
diff --git a/test/runtime/samples/bindings-coalesced/Foo.html b/test/runtime/samples/bindings-coalesced/Foo.svelte
similarity index 100%
rename from test/runtime/samples/bindings-coalesced/Foo.html
rename to test/runtime/samples/bindings-coalesced/Foo.svelte
diff --git a/test/runtime/samples/bindings-coalesced/main.html b/test/runtime/samples/bindings-coalesced/main.svelte
similarity index 66%
rename from test/runtime/samples/bindings-coalesced/main.html
rename to test/runtime/samples/bindings-coalesced/main.svelte
index cf0b85491a..003f89c6d9 100644
--- a/test/runtime/samples/bindings-coalesced/main.html
+++ b/test/runtime/samples/bindings-coalesced/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Foo from './Foo.html';
+	import Foo from './Foo.svelte';
 
 	export let p;
 
diff --git a/test/runtime/samples/class-boolean/main.html b/test/runtime/samples/class-boolean/main.svelte
similarity index 100%
rename from test/runtime/samples/class-boolean/main.html
rename to test/runtime/samples/class-boolean/main.svelte
diff --git a/test/runtime/samples/class-helper/main.html b/test/runtime/samples/class-helper/main.svelte
similarity index 100%
rename from test/runtime/samples/class-helper/main.html
rename to test/runtime/samples/class-helper/main.svelte
diff --git a/test/runtime/samples/class-in-each/main.html b/test/runtime/samples/class-in-each/main.svelte
similarity index 100%
rename from test/runtime/samples/class-in-each/main.html
rename to test/runtime/samples/class-in-each/main.svelte
diff --git a/test/runtime/samples/class-shortcut-with-class/main.html b/test/runtime/samples/class-shortcut-with-class/main.svelte
similarity index 100%
rename from test/runtime/samples/class-shortcut-with-class/main.html
rename to test/runtime/samples/class-shortcut-with-class/main.svelte
diff --git a/test/runtime/samples/class-shortcut/main.html b/test/runtime/samples/class-shortcut/main.svelte
similarity index 100%
rename from test/runtime/samples/class-shortcut/main.html
rename to test/runtime/samples/class-shortcut/main.svelte
diff --git a/test/runtime/samples/class-with-attribute/main.html b/test/runtime/samples/class-with-attribute/main.svelte
similarity index 100%
rename from test/runtime/samples/class-with-attribute/main.html
rename to test/runtime/samples/class-with-attribute/main.svelte
diff --git a/test/runtime/samples/class-with-dynamic-attribute/main.html b/test/runtime/samples/class-with-dynamic-attribute/main.svelte
similarity index 100%
rename from test/runtime/samples/class-with-dynamic-attribute/main.html
rename to test/runtime/samples/class-with-dynamic-attribute/main.svelte
diff --git a/test/runtime/samples/component-binding-blowback-b/Nested.html b/test/runtime/samples/component-binding-blowback-b/Nested.svelte
similarity index 100%
rename from test/runtime/samples/component-binding-blowback-b/Nested.html
rename to test/runtime/samples/component-binding-blowback-b/Nested.svelte
diff --git a/test/runtime/samples/component-binding-blowback-b/main.html b/test/runtime/samples/component-binding-blowback-b/main.svelte
similarity index 88%
rename from test/runtime/samples/component-binding-blowback-b/main.html
rename to test/runtime/samples/component-binding-blowback-b/main.svelte
index 327b64ca09..92a618f67c 100644
--- a/test/runtime/samples/component-binding-blowback-b/main.html
+++ b/test/runtime/samples/component-binding-blowback-b/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Nested from './Nested.html';
+	import Nested from './Nested.svelte';
 
 	export let count;
 	export let idToValue = Object.create(null);
diff --git a/test/runtime/samples/component-binding-blowback-c/Nested.html b/test/runtime/samples/component-binding-blowback-c/Nested.svelte
similarity index 100%
rename from test/runtime/samples/component-binding-blowback-c/Nested.html
rename to test/runtime/samples/component-binding-blowback-c/Nested.svelte
diff --git a/test/runtime/samples/component-binding-blowback-c/main.html b/test/runtime/samples/component-binding-blowback-c/main.svelte
similarity index 90%
rename from test/runtime/samples/component-binding-blowback-c/main.html
rename to test/runtime/samples/component-binding-blowback-c/main.svelte
index 1360229444..4876af13a8 100644
--- a/test/runtime/samples/component-binding-blowback-c/main.html
+++ b/test/runtime/samples/component-binding-blowback-c/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Nested from './Nested.html';
+	import Nested from './Nested.svelte';
 
 	export let count;
 	export let idToValue = Object.create(null);
diff --git a/test/runtime/samples/component-binding-blowback/Widget.html b/test/runtime/samples/component-binding-blowback/Widget.svelte
similarity index 100%
rename from test/runtime/samples/component-binding-blowback/Widget.html
rename to test/runtime/samples/component-binding-blowback/Widget.svelte
diff --git a/test/runtime/samples/component-binding-blowback/main.html b/test/runtime/samples/component-binding-blowback/main.svelte
similarity index 72%
rename from test/runtime/samples/component-binding-blowback/main.html
rename to test/runtime/samples/component-binding-blowback/main.svelte
index f51c889fc3..cd2e4d1c3b 100644
--- a/test/runtime/samples/component-binding-blowback/main.html
+++ b/test/runtime/samples/component-binding-blowback/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Widget from './Widget.html';
+	import Widget from './Widget.svelte';
 
 	export let x = false;
 	export let bar = {
diff --git a/test/runtime/samples/component-binding-computed/Nested.html b/test/runtime/samples/component-binding-computed/Nested.svelte
similarity index 100%
rename from test/runtime/samples/component-binding-computed/Nested.html
rename to test/runtime/samples/component-binding-computed/Nested.svelte
diff --git a/test/runtime/samples/component-binding-computed/main.html b/test/runtime/samples/component-binding-computed/main.svelte
similarity index 81%
rename from test/runtime/samples/component-binding-computed/main.html
rename to test/runtime/samples/component-binding-computed/main.svelte
index f1b9be4e16..e9b5a1be92 100644
--- a/test/runtime/samples/component-binding-computed/main.html
+++ b/test/runtime/samples/component-binding-computed/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Nested from './Nested.html';
+	import Nested from './Nested.svelte';
 
 	export let fields = ['firstname', 'lastname'];
 	export let values = {
diff --git a/test/runtime/samples/component-binding-conditional-b/Bar.html b/test/runtime/samples/component-binding-conditional-b/Bar.svelte
similarity index 100%
rename from test/runtime/samples/component-binding-conditional-b/Bar.html
rename to test/runtime/samples/component-binding-conditional-b/Bar.svelte
diff --git a/test/runtime/samples/component-binding-conditional-b/Baz.html b/test/runtime/samples/component-binding-conditional-b/Baz.svelte
similarity index 100%
rename from test/runtime/samples/component-binding-conditional-b/Baz.html
rename to test/runtime/samples/component-binding-conditional-b/Baz.svelte
diff --git a/test/runtime/samples/component-binding-conditional-b/Foo.html b/test/runtime/samples/component-binding-conditional-b/Foo.svelte
similarity index 100%
rename from test/runtime/samples/component-binding-conditional-b/Foo.html
rename to test/runtime/samples/component-binding-conditional-b/Foo.svelte
diff --git a/test/runtime/samples/component-binding-conditional-b/main.html b/test/runtime/samples/component-binding-conditional-b/main.svelte
similarity index 54%
rename from test/runtime/samples/component-binding-conditional-b/main.html
rename to test/runtime/samples/component-binding-conditional-b/main.svelte
index a96c8b671d..568fb031fb 100644
--- a/test/runtime/samples/component-binding-conditional-b/main.html
+++ b/test/runtime/samples/component-binding-conditional-b/main.svelte
@@ -1,7 +1,7 @@
 <script>
-	import Foo from './Foo.html';
-	import Bar from './Bar.html';
-	import Baz from './Baz.html';
+	import Foo from './Foo.svelte';
+	import Bar from './Bar.svelte';
+	import Baz from './Baz.svelte';
 
 	export let y;
 	export let x;
diff --git a/test/runtime/samples/component-binding-conditional/Bar.html b/test/runtime/samples/component-binding-conditional/Bar.svelte
similarity index 100%
rename from test/runtime/samples/component-binding-conditional/Bar.html
rename to test/runtime/samples/component-binding-conditional/Bar.svelte
diff --git a/test/runtime/samples/component-binding-conditional/Baz.html b/test/runtime/samples/component-binding-conditional/Baz.svelte
similarity index 100%
rename from test/runtime/samples/component-binding-conditional/Baz.html
rename to test/runtime/samples/component-binding-conditional/Baz.svelte
diff --git a/test/runtime/samples/component-binding-conditional/Foo.html b/test/runtime/samples/component-binding-conditional/Foo.svelte
similarity index 100%
rename from test/runtime/samples/component-binding-conditional/Foo.html
rename to test/runtime/samples/component-binding-conditional/Foo.svelte
diff --git a/test/runtime/samples/component-binding-conditional/main.html b/test/runtime/samples/component-binding-conditional/main.svelte
similarity index 51%
rename from test/runtime/samples/component-binding-conditional/main.html
rename to test/runtime/samples/component-binding-conditional/main.svelte
index 9316eb5866..fee850a65a 100644
--- a/test/runtime/samples/component-binding-conditional/main.html
+++ b/test/runtime/samples/component-binding-conditional/main.svelte
@@ -1,7 +1,7 @@
 <script>
-	import Foo from './Foo.html';
-	import Bar from './Bar.html';
-	import Baz from './Baz.html';
+	import Foo from './Foo.svelte';
+	import Bar from './Bar.svelte';
+	import Baz from './Baz.svelte';
 
 	export let y;
 	export let x;
diff --git a/test/runtime/samples/component-binding-deep-b/ComponentSelector.html b/test/runtime/samples/component-binding-deep-b/ComponentSelector.svelte
similarity index 100%
rename from test/runtime/samples/component-binding-deep-b/ComponentSelector.html
rename to test/runtime/samples/component-binding-deep-b/ComponentSelector.svelte
diff --git a/test/runtime/samples/component-binding-deep-b/Editor.html b/test/runtime/samples/component-binding-deep-b/Editor.svelte
similarity index 100%
rename from test/runtime/samples/component-binding-deep-b/Editor.html
rename to test/runtime/samples/component-binding-deep-b/Editor.svelte
diff --git a/test/runtime/samples/component-binding-deep-b/main.html b/test/runtime/samples/component-binding-deep-b/main.svelte
similarity index 88%
rename from test/runtime/samples/component-binding-deep-b/main.html
rename to test/runtime/samples/component-binding-deep-b/main.svelte
index a2de980483..a96f65a30e 100644
--- a/test/runtime/samples/component-binding-deep-b/main.html
+++ b/test/runtime/samples/component-binding-deep-b/main.svelte
@@ -1,8 +1,8 @@
 <script>
 	import { beforeUpdate } from 'svelte';
 
-	import Editor from './Editor.html';
-	import ComponentSelector from './ComponentSelector.html';
+	import Editor from './Editor.svelte';
+	import ComponentSelector from './ComponentSelector.svelte';
 
 	export let components;
 	export let selectedComponent;
diff --git a/test/runtime/samples/component-binding-deep/Widget.html b/test/runtime/samples/component-binding-deep/Widget.svelte
similarity index 100%
rename from test/runtime/samples/component-binding-deep/Widget.html
rename to test/runtime/samples/component-binding-deep/Widget.svelte
diff --git a/test/runtime/samples/component-binding-deep/main.html b/test/runtime/samples/component-binding-deep/main.svelte
similarity index 62%
rename from test/runtime/samples/component-binding-deep/main.html
rename to test/runtime/samples/component-binding-deep/main.svelte
index 720ac74dd7..a364a91e3f 100644
--- a/test/runtime/samples/component-binding-deep/main.html
+++ b/test/runtime/samples/component-binding-deep/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Widget from './Widget.html';
+	import Widget from './Widget.svelte';
 
 	export let deep = {
 		name: 'foo'
diff --git a/test/runtime/samples/component-binding-each-nested/Widget.html b/test/runtime/samples/component-binding-each-nested/Widget.svelte
similarity index 100%
rename from test/runtime/samples/component-binding-each-nested/Widget.html
rename to test/runtime/samples/component-binding-each-nested/Widget.svelte
diff --git a/test/runtime/samples/component-binding-each-nested/main.html b/test/runtime/samples/component-binding-each-nested/main.svelte
similarity index 71%
rename from test/runtime/samples/component-binding-each-nested/main.html
rename to test/runtime/samples/component-binding-each-nested/main.svelte
index db8b232336..3ac4638c9a 100644
--- a/test/runtime/samples/component-binding-each-nested/main.html
+++ b/test/runtime/samples/component-binding-each-nested/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Widget from './Widget.html';
+	import Widget from './Widget.svelte';
 
 	export let a = [{ name: 'foo' }, { name: 'bar' }, { name: 'baz' }];
 	export let getName = x => x.name;
diff --git a/test/runtime/samples/component-binding-each-object/Widget.html b/test/runtime/samples/component-binding-each-object/Widget.svelte
similarity index 100%
rename from test/runtime/samples/component-binding-each-object/Widget.html
rename to test/runtime/samples/component-binding-each-object/Widget.svelte
diff --git a/test/runtime/samples/component-binding-each-object/main.html b/test/runtime/samples/component-binding-each-object/main.svelte
similarity index 62%
rename from test/runtime/samples/component-binding-each-object/main.html
rename to test/runtime/samples/component-binding-each-object/main.svelte
index 1efb284666..4f77440ae0 100644
--- a/test/runtime/samples/component-binding-each-object/main.html
+++ b/test/runtime/samples/component-binding-each-object/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Widget from './Widget.html';
+	import Widget from './Widget.svelte';
 
 	export let a;
 </script>
diff --git a/test/runtime/samples/component-binding-each/Widget.html b/test/runtime/samples/component-binding-each/Widget.svelte
similarity index 100%
rename from test/runtime/samples/component-binding-each/Widget.html
rename to test/runtime/samples/component-binding-each/Widget.svelte
diff --git a/test/runtime/samples/component-binding-each/main.html b/test/runtime/samples/component-binding-each/main.svelte
similarity index 64%
rename from test/runtime/samples/component-binding-each/main.html
rename to test/runtime/samples/component-binding-each/main.svelte
index 49ab04e68f..36a7c46225 100644
--- a/test/runtime/samples/component-binding-each/main.html
+++ b/test/runtime/samples/component-binding-each/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Widget from './Widget.html';
+	import Widget from './Widget.svelte';
 
 	export let a = ['foo', 'bar', 'baz'];
 </script>
diff --git a/test/runtime/samples/component-binding-infinite-loop/A.html b/test/runtime/samples/component-binding-infinite-loop/A.svelte
similarity index 58%
rename from test/runtime/samples/component-binding-infinite-loop/A.html
rename to test/runtime/samples/component-binding-infinite-loop/A.svelte
index d4a9bf8eac..8ba3ec20f3 100644
--- a/test/runtime/samples/component-binding-infinite-loop/A.html
+++ b/test/runtime/samples/component-binding-infinite-loop/A.svelte
@@ -1,5 +1,5 @@
 <script>
-	import B from './B.html';
+	import B from './B.svelte';
 
 	export let currentIdentifier;
 </script>
diff --git a/test/runtime/samples/component-binding-infinite-loop/B.html b/test/runtime/samples/component-binding-infinite-loop/B.svelte
similarity index 83%
rename from test/runtime/samples/component-binding-infinite-loop/B.html
rename to test/runtime/samples/component-binding-infinite-loop/B.svelte
index 72bbbe4110..cbc8160679 100644
--- a/test/runtime/samples/component-binding-infinite-loop/B.html
+++ b/test/runtime/samples/component-binding-infinite-loop/B.svelte
@@ -1,5 +1,5 @@
 <script>
-	import C from './C.html';
+	import C from './C.svelte';
 
 	export let list = [1, 2, 3, 2, 1];
 	export let currentIdentifier;
diff --git a/test/runtime/samples/component-binding-infinite-loop/C.html b/test/runtime/samples/component-binding-infinite-loop/C.svelte
similarity index 100%
rename from test/runtime/samples/component-binding-infinite-loop/C.html
rename to test/runtime/samples/component-binding-infinite-loop/C.svelte
diff --git a/test/runtime/samples/component-binding-infinite-loop/main.html b/test/runtime/samples/component-binding-infinite-loop/main.svelte
similarity index 59%
rename from test/runtime/samples/component-binding-infinite-loop/main.html
rename to test/runtime/samples/component-binding-infinite-loop/main.svelte
index b896316960..6556a7c12a 100644
--- a/test/runtime/samples/component-binding-infinite-loop/main.html
+++ b/test/runtime/samples/component-binding-infinite-loop/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import A from './A.html';
+	import A from './A.svelte';
 
 	export let currentIdentifier = 2;
 </script>
diff --git a/test/runtime/samples/component-binding-nested/Bar.html b/test/runtime/samples/component-binding-nested/Bar.svelte
similarity index 71%
rename from test/runtime/samples/component-binding-nested/Bar.html
rename to test/runtime/samples/component-binding-nested/Bar.svelte
index 9ed5c6f42c..19159f168d 100644
--- a/test/runtime/samples/component-binding-nested/Bar.html
+++ b/test/runtime/samples/component-binding-nested/Bar.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Baz from './Baz.html';
+	import Baz from './Baz.svelte';
 
 	export let x;
 </script>
diff --git a/test/runtime/samples/component-binding-nested/Baz.html b/test/runtime/samples/component-binding-nested/Baz.svelte
similarity index 100%
rename from test/runtime/samples/component-binding-nested/Baz.html
rename to test/runtime/samples/component-binding-nested/Baz.svelte
diff --git a/test/runtime/samples/component-binding-nested/Foo.html b/test/runtime/samples/component-binding-nested/Foo.svelte
similarity index 71%
rename from test/runtime/samples/component-binding-nested/Foo.html
rename to test/runtime/samples/component-binding-nested/Foo.svelte
index 500480eae6..4a3e59afe7 100644
--- a/test/runtime/samples/component-binding-nested/Foo.html
+++ b/test/runtime/samples/component-binding-nested/Foo.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Bar from './Bar.html';
+	import Bar from './Bar.svelte';
 
 	export let x;
 </script>
diff --git a/test/runtime/samples/component-binding-nested/main.html b/test/runtime/samples/component-binding-nested/main.svelte
similarity index 52%
rename from test/runtime/samples/component-binding-nested/main.html
rename to test/runtime/samples/component-binding-nested/main.svelte
index cae8f4dc52..18f96b310c 100644
--- a/test/runtime/samples/component-binding-nested/main.html
+++ b/test/runtime/samples/component-binding-nested/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Foo from './Foo.html';
+	import Foo from './Foo.svelte';
 
 	export let x;
 </script>
diff --git a/test/runtime/samples/component-binding-parent-supercedes-child-b/Bar.html b/test/runtime/samples/component-binding-parent-supercedes-child-b/Bar.svelte
similarity index 100%
rename from test/runtime/samples/component-binding-parent-supercedes-child-b/Bar.html
rename to test/runtime/samples/component-binding-parent-supercedes-child-b/Bar.svelte
diff --git a/test/runtime/samples/component-binding-parent-supercedes-child-b/Foo.html b/test/runtime/samples/component-binding-parent-supercedes-child-b/Foo.svelte
similarity index 100%
rename from test/runtime/samples/component-binding-parent-supercedes-child-b/Foo.html
rename to test/runtime/samples/component-binding-parent-supercedes-child-b/Foo.svelte
diff --git a/test/runtime/samples/component-binding-parent-supercedes-child-b/main.html b/test/runtime/samples/component-binding-parent-supercedes-child-b/main.svelte
similarity index 55%
rename from test/runtime/samples/component-binding-parent-supercedes-child-b/main.html
rename to test/runtime/samples/component-binding-parent-supercedes-child-b/main.svelte
index aaad9eb2fe..e6edf3b1f7 100644
--- a/test/runtime/samples/component-binding-parent-supercedes-child-b/main.html
+++ b/test/runtime/samples/component-binding-parent-supercedes-child-b/main.svelte
@@ -1,6 +1,6 @@
 <script>
-	import Foo from './Foo.html';
-	import Bar from './Bar.html';
+	import Foo from './Foo.svelte';
+	import Bar from './Bar.svelte';
 
 	export let a = true;
 	export let x;
diff --git a/test/runtime/samples/component-binding-parent-supercedes-child-c/Bar.html b/test/runtime/samples/component-binding-parent-supercedes-child-c/Bar.svelte
similarity index 100%
rename from test/runtime/samples/component-binding-parent-supercedes-child-c/Bar.html
rename to test/runtime/samples/component-binding-parent-supercedes-child-c/Bar.svelte
diff --git a/test/runtime/samples/component-binding-parent-supercedes-child-c/Foo.html b/test/runtime/samples/component-binding-parent-supercedes-child-c/Foo.svelte
similarity index 100%
rename from test/runtime/samples/component-binding-parent-supercedes-child-c/Foo.html
rename to test/runtime/samples/component-binding-parent-supercedes-child-c/Foo.svelte
diff --git a/test/runtime/samples/component-binding-parent-supercedes-child-c/main.html b/test/runtime/samples/component-binding-parent-supercedes-child-c/main.svelte
similarity index 55%
rename from test/runtime/samples/component-binding-parent-supercedes-child-c/main.html
rename to test/runtime/samples/component-binding-parent-supercedes-child-c/main.svelte
index ffc5bd188d..426ef04bad 100644
--- a/test/runtime/samples/component-binding-parent-supercedes-child-c/main.html
+++ b/test/runtime/samples/component-binding-parent-supercedes-child-c/main.svelte
@@ -1,6 +1,6 @@
 <script>
-	import Foo from './Foo.html';
-	import Bar from './Bar.html';
+	import Foo from './Foo.svelte';
+	import Bar from './Bar.svelte';
 
 	export let a = true;
 	export let x;
diff --git a/test/runtime/samples/component-binding-parent-supercedes-child/Counter.html b/test/runtime/samples/component-binding-parent-supercedes-child/Counter.svelte
similarity index 100%
rename from test/runtime/samples/component-binding-parent-supercedes-child/Counter.html
rename to test/runtime/samples/component-binding-parent-supercedes-child/Counter.svelte
diff --git a/test/runtime/samples/component-binding-parent-supercedes-child/main.html b/test/runtime/samples/component-binding-parent-supercedes-child/main.svelte
similarity index 53%
rename from test/runtime/samples/component-binding-parent-supercedes-child/main.html
rename to test/runtime/samples/component-binding-parent-supercedes-child/main.svelte
index c874b270d0..e38b72daae 100644
--- a/test/runtime/samples/component-binding-parent-supercedes-child/main.html
+++ b/test/runtime/samples/component-binding-parent-supercedes-child/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Counter from './Counter.html';
+	import Counter from './Counter.svelte';
 
 	export let x = 10;
 </script>
diff --git a/test/runtime/samples/component-binding-private-state/Bar.html b/test/runtime/samples/component-binding-private-state/Bar.svelte
similarity index 100%
rename from test/runtime/samples/component-binding-private-state/Bar.html
rename to test/runtime/samples/component-binding-private-state/Bar.svelte
diff --git a/test/runtime/samples/component-binding-private-state/Foo.html b/test/runtime/samples/component-binding-private-state/Foo.svelte
similarity index 100%
rename from test/runtime/samples/component-binding-private-state/Foo.html
rename to test/runtime/samples/component-binding-private-state/Foo.svelte
diff --git a/test/runtime/samples/component-binding-private-state/main.html b/test/runtime/samples/component-binding-private-state/main.svelte
similarity index 55%
rename from test/runtime/samples/component-binding-private-state/main.html
rename to test/runtime/samples/component-binding-private-state/main.svelte
index ffc5bd188d..426ef04bad 100644
--- a/test/runtime/samples/component-binding-private-state/main.html
+++ b/test/runtime/samples/component-binding-private-state/main.svelte
@@ -1,6 +1,6 @@
 <script>
-	import Foo from './Foo.html';
-	import Bar from './Bar.html';
+	import Foo from './Foo.svelte';
+	import Bar from './Bar.svelte';
 
 	export let a = true;
 	export let x;
diff --git a/test/runtime/samples/component-binding-self-destroying/Nested.html b/test/runtime/samples/component-binding-self-destroying/Nested.svelte
similarity index 100%
rename from test/runtime/samples/component-binding-self-destroying/Nested.html
rename to test/runtime/samples/component-binding-self-destroying/Nested.svelte
diff --git a/test/runtime/samples/component-binding-self-destroying/main.html b/test/runtime/samples/component-binding-self-destroying/main.svelte
similarity index 75%
rename from test/runtime/samples/component-binding-self-destroying/main.html
rename to test/runtime/samples/component-binding-self-destroying/main.svelte
index 66b578f9bc..7043a52ad4 100644
--- a/test/runtime/samples/component-binding-self-destroying/main.html
+++ b/test/runtime/samples/component-binding-self-destroying/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Nested from './Nested.html';
+	import Nested from './Nested.svelte';
 	export let show;
 </script>
 
diff --git a/test/runtime/samples/component-binding/Counter.html b/test/runtime/samples/component-binding/Counter.svelte
similarity index 100%
rename from test/runtime/samples/component-binding/Counter.html
rename to test/runtime/samples/component-binding/Counter.svelte
diff --git a/test/runtime/samples/component-binding/main.html b/test/runtime/samples/component-binding/main.svelte
similarity index 51%
rename from test/runtime/samples/component-binding/main.html
rename to test/runtime/samples/component-binding/main.svelte
index 5639d47eb1..3a582fe7bd 100644
--- a/test/runtime/samples/component-binding/main.html
+++ b/test/runtime/samples/component-binding/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Counter from './Counter.html';
+	import Counter from './Counter.svelte';
 
 	export let x;
 </script>
diff --git a/test/runtime/samples/component-data-dynamic-late/Widget.html b/test/runtime/samples/component-data-dynamic-late/Widget.svelte
similarity index 100%
rename from test/runtime/samples/component-data-dynamic-late/Widget.html
rename to test/runtime/samples/component-data-dynamic-late/Widget.svelte
diff --git a/test/runtime/samples/component-data-dynamic-late/main.html b/test/runtime/samples/component-data-dynamic-late/main.svelte
similarity index 67%
rename from test/runtime/samples/component-data-dynamic-late/main.html
rename to test/runtime/samples/component-data-dynamic-late/main.svelte
index 4c07837598..4e11d151cf 100644
--- a/test/runtime/samples/component-data-dynamic-late/main.html
+++ b/test/runtime/samples/component-data-dynamic-late/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Widget from './Widget.html';
+	import Widget from './Widget.svelte';
 
 	export let foo = false;
 	export let q;
diff --git a/test/runtime/samples/component-data-dynamic-shorthand/Widget.html b/test/runtime/samples/component-data-dynamic-shorthand/Widget.svelte
similarity index 100%
rename from test/runtime/samples/component-data-dynamic-shorthand/Widget.html
rename to test/runtime/samples/component-data-dynamic-shorthand/Widget.svelte
diff --git a/test/runtime/samples/component-data-dynamic-shorthand/main.html b/test/runtime/samples/component-data-dynamic-shorthand/main.svelte
similarity index 57%
rename from test/runtime/samples/component-data-dynamic-shorthand/main.html
rename to test/runtime/samples/component-data-dynamic-shorthand/main.svelte
index c6359fbc25..6245b9064b 100644
--- a/test/runtime/samples/component-data-dynamic-shorthand/main.html
+++ b/test/runtime/samples/component-data-dynamic-shorthand/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Widget from './Widget.html';
+	import Widget from './Widget.svelte';
 
 	export let foo;
 </script>
diff --git a/test/runtime/samples/component-data-dynamic/Widget.html b/test/runtime/samples/component-data-dynamic/Widget.svelte
similarity index 100%
rename from test/runtime/samples/component-data-dynamic/Widget.html
rename to test/runtime/samples/component-data-dynamic/Widget.svelte
diff --git a/test/runtime/samples/component-data-dynamic/main.html b/test/runtime/samples/component-data-dynamic/main.svelte
similarity index 80%
rename from test/runtime/samples/component-data-dynamic/main.html
rename to test/runtime/samples/component-data-dynamic/main.svelte
index 7c796ca9b6..42ef74a185 100644
--- a/test/runtime/samples/component-data-dynamic/main.html
+++ b/test/runtime/samples/component-data-dynamic/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Widget from './Widget.html';
+	import Widget from './Widget.svelte';
 
 	export let bar;
 	export let x;
diff --git a/test/runtime/samples/component-data-empty/Widget.html b/test/runtime/samples/component-data-empty/Widget.svelte
similarity index 100%
rename from test/runtime/samples/component-data-empty/Widget.html
rename to test/runtime/samples/component-data-empty/Widget.svelte
diff --git a/test/runtime/samples/component-data-empty/main.html b/test/runtime/samples/component-data-empty/main.html
deleted file mode 100644
index 3989cd2319..0000000000
--- a/test/runtime/samples/component-data-empty/main.html
+++ /dev/null
@@ -1,7 +0,0 @@
-<script>
-	import Widget from './Widget.html';
-</script>
-
-<div>
-	<Widget foo=''/>
-</div>
\ No newline at end of file
diff --git a/test/runtime/samples/component-data-empty/main.svelte b/test/runtime/samples/component-data-empty/main.svelte
new file mode 100644
index 0000000000..be6a137e8a
--- /dev/null
+++ b/test/runtime/samples/component-data-empty/main.svelte
@@ -0,0 +1,7 @@
+<script>
+	import Widget from './Widget.svelte';
+</script>
+
+<div>
+	<Widget foo=''/>
+</div>
\ No newline at end of file
diff --git a/test/runtime/samples/component-data-static-boolean-regression/Link.html b/test/runtime/samples/component-data-static-boolean-regression/Link.svelte
similarity index 100%
rename from test/runtime/samples/component-data-static-boolean-regression/Link.html
rename to test/runtime/samples/component-data-static-boolean-regression/Link.svelte
diff --git a/test/runtime/samples/component-data-static-boolean-regression/main.html b/test/runtime/samples/component-data-static-boolean-regression/main.html
deleted file mode 100644
index 8207fef20e..0000000000
--- a/test/runtime/samples/component-data-static-boolean-regression/main.html
+++ /dev/null
@@ -1,5 +0,0 @@
-<script>
-	import Link from './Link.html';
-</script>
-
-<Link x href="/cool"/>
\ No newline at end of file
diff --git a/test/runtime/samples/component-data-static-boolean-regression/main.svelte b/test/runtime/samples/component-data-static-boolean-regression/main.svelte
new file mode 100644
index 0000000000..492d1dc78a
--- /dev/null
+++ b/test/runtime/samples/component-data-static-boolean-regression/main.svelte
@@ -0,0 +1,5 @@
+<script>
+	import Link from './Link.svelte';
+</script>
+
+<Link x href="/cool"/>
\ No newline at end of file
diff --git a/test/runtime/samples/component-data-static-boolean/Foo.html b/test/runtime/samples/component-data-static-boolean/Foo.svelte
similarity index 100%
rename from test/runtime/samples/component-data-static-boolean/Foo.html
rename to test/runtime/samples/component-data-static-boolean/Foo.svelte
diff --git a/test/runtime/samples/component-data-static-boolean/main.html b/test/runtime/samples/component-data-static-boolean/main.html
deleted file mode 100644
index cfaef9dea3..0000000000
--- a/test/runtime/samples/component-data-static-boolean/main.html
+++ /dev/null
@@ -1,5 +0,0 @@
-<script>
-	import Foo from './Foo.html';
-</script>
-
-<Foo x/>
\ No newline at end of file
diff --git a/test/runtime/samples/component-data-static-boolean/main.svelte b/test/runtime/samples/component-data-static-boolean/main.svelte
new file mode 100644
index 0000000000..edb8e749af
--- /dev/null
+++ b/test/runtime/samples/component-data-static-boolean/main.svelte
@@ -0,0 +1,5 @@
+<script>
+	import Foo from './Foo.svelte';
+</script>
+
+<Foo x/>
\ No newline at end of file
diff --git a/test/runtime/samples/component-data-static/Widget.html b/test/runtime/samples/component-data-static/Widget.svelte
similarity index 100%
rename from test/runtime/samples/component-data-static/Widget.html
rename to test/runtime/samples/component-data-static/Widget.svelte
diff --git a/test/runtime/samples/component-data-static/main.html b/test/runtime/samples/component-data-static/main.svelte
similarity index 55%
rename from test/runtime/samples/component-data-static/main.html
rename to test/runtime/samples/component-data-static/main.svelte
index ec8e37c45e..b116b262a0 100644
--- a/test/runtime/samples/component-data-static/main.html
+++ b/test/runtime/samples/component-data-static/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Widget from './Widget.html';
+	import Widget from './Widget.svelte';
 </script>
 
 <div>
diff --git a/test/runtime/samples/component-event-not-stale/Button.html b/test/runtime/samples/component-event-not-stale/Button.svelte
similarity index 100%
rename from test/runtime/samples/component-event-not-stale/Button.html
rename to test/runtime/samples/component-event-not-stale/Button.svelte
diff --git a/test/runtime/samples/component-event-not-stale/main.html b/test/runtime/samples/component-event-not-stale/main.svelte
similarity index 88%
rename from test/runtime/samples/component-event-not-stale/main.html
rename to test/runtime/samples/component-event-not-stale/main.svelte
index 1beacd0e2d..0b2ab2c1ee 100644
--- a/test/runtime/samples/component-event-not-stale/main.html
+++ b/test/runtime/samples/component-event-not-stale/main.svelte
@@ -1,6 +1,6 @@
 <script>
 	import { createEventDispatcher } from 'svelte';
-	import Button from './Button.html';
+	import Button from './Button.svelte';
 
 	const dispatch = createEventDispatcher();
 
diff --git a/test/runtime/samples/component-events-console/Widget.html b/test/runtime/samples/component-events-console/Widget.svelte
similarity index 100%
rename from test/runtime/samples/component-events-console/Widget.html
rename to test/runtime/samples/component-events-console/Widget.svelte
diff --git a/test/runtime/samples/component-events-console/main.html b/test/runtime/samples/component-events-console/main.html
deleted file mode 100644
index 7b0c3fccda..0000000000
--- a/test/runtime/samples/component-events-console/main.html
+++ /dev/null
@@ -1,5 +0,0 @@
-<script>
-	import Widget from './Widget.html';
-</script>
-
-<Widget on:click="{() => console.log('clicked')}"/>
\ No newline at end of file
diff --git a/test/runtime/samples/component-events-console/main.svelte b/test/runtime/samples/component-events-console/main.svelte
new file mode 100644
index 0000000000..fba004b4eb
--- /dev/null
+++ b/test/runtime/samples/component-events-console/main.svelte
@@ -0,0 +1,5 @@
+<script>
+	import Widget from './Widget.svelte';
+</script>
+
+<Widget on:click="{() => console.log('clicked')}"/>
\ No newline at end of file
diff --git a/test/runtime/samples/component-events-data/Widget.html b/test/runtime/samples/component-events-data/Widget.svelte
similarity index 100%
rename from test/runtime/samples/component-events-data/Widget.html
rename to test/runtime/samples/component-events-data/Widget.svelte
diff --git a/test/runtime/samples/component-events-data/main.html b/test/runtime/samples/component-events-data/main.svelte
similarity index 81%
rename from test/runtime/samples/component-events-data/main.html
rename to test/runtime/samples/component-events-data/main.svelte
index 5661404a46..ea44594ccd 100644
--- a/test/runtime/samples/component-events-data/main.html
+++ b/test/runtime/samples/component-events-data/main.svelte
@@ -1,6 +1,6 @@
 <script>
 	import { createEventDispatcher } from 'svelte';
-	import Widget from './Widget.html';
+	import Widget from './Widget.svelte';
 
 	const dispatch = createEventDispatcher();
 </script>
diff --git a/test/runtime/samples/component-events-each/Widget.html b/test/runtime/samples/component-events-each/Widget.svelte
similarity index 100%
rename from test/runtime/samples/component-events-each/Widget.html
rename to test/runtime/samples/component-events-each/Widget.svelte
diff --git a/test/runtime/samples/component-events-each/main.html b/test/runtime/samples/component-events-each/main.svelte
similarity index 85%
rename from test/runtime/samples/component-events-each/main.html
rename to test/runtime/samples/component-events-each/main.svelte
index 4a5a694172..f229873431 100644
--- a/test/runtime/samples/component-events-each/main.html
+++ b/test/runtime/samples/component-events-each/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Widget from './Widget.html';
+	import Widget from './Widget.svelte';
 	import { createEventDispatcher } from 'svelte';
 
 	const dispatch = createEventDispatcher();
diff --git a/test/runtime/samples/component-events/Widget.html b/test/runtime/samples/component-events/Widget.svelte
similarity index 100%
rename from test/runtime/samples/component-events/Widget.html
rename to test/runtime/samples/component-events/Widget.svelte
diff --git a/test/runtime/samples/component-events/main.html b/test/runtime/samples/component-events/main.svelte
similarity index 83%
rename from test/runtime/samples/component-events/main.html
rename to test/runtime/samples/component-events/main.svelte
index fc4839e027..ad33261456 100644
--- a/test/runtime/samples/component-events/main.html
+++ b/test/runtime/samples/component-events/main.svelte
@@ -1,6 +1,6 @@
 <script>
 	import { createEventDispatcher } from 'svelte';
-	import Widget from './Widget.html';
+	import Widget from './Widget.svelte';
 
 	const dispatch = createEventDispatcher();
 
diff --git a/test/runtime/samples/component-if-placement/Component.html b/test/runtime/samples/component-if-placement/Component.svelte
similarity index 100%
rename from test/runtime/samples/component-if-placement/Component.html
rename to test/runtime/samples/component-if-placement/Component.svelte
diff --git a/test/runtime/samples/component-if-placement/main.html b/test/runtime/samples/component-if-placement/main.svelte
similarity index 63%
rename from test/runtime/samples/component-if-placement/main.html
rename to test/runtime/samples/component-if-placement/main.svelte
index 175feeb6b5..f9e65b9d3b 100644
--- a/test/runtime/samples/component-if-placement/main.html
+++ b/test/runtime/samples/component-if-placement/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Component from './Component.html';
+	import Component from './Component.svelte';
 	export let flag;
 </script>
 
diff --git a/test/runtime/samples/component-name-deconflicted/Nested.html b/test/runtime/samples/component-name-deconflicted/Nested.svelte
similarity index 100%
rename from test/runtime/samples/component-name-deconflicted/Nested.html
rename to test/runtime/samples/component-name-deconflicted/Nested.svelte
diff --git a/test/runtime/samples/component-name-deconflicted/main.html b/test/runtime/samples/component-name-deconflicted/main.svelte
similarity index 70%
rename from test/runtime/samples/component-name-deconflicted/main.html
rename to test/runtime/samples/component-name-deconflicted/main.svelte
index 03d43c357b..1649ad0a7d 100644
--- a/test/runtime/samples/component-name-deconflicted/main.html
+++ b/test/runtime/samples/component-name-deconflicted/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Nested from './Nested.html';
+	import Nested from './Nested.svelte';
 
 	export let list = [1, 2];
 </script>
diff --git a/test/runtime/samples/component-nested-deep/Level1.html b/test/runtime/samples/component-nested-deep/Level1.html
deleted file mode 100644
index 246bc4dfb7..0000000000
--- a/test/runtime/samples/component-nested-deep/Level1.html
+++ /dev/null
@@ -1,8 +0,0 @@
-<script>
-	import Level2 from './Level2.html';
-	import Level3 from './Level3.html';
-</script>
-
-<Level2>
-	<Level3 />
-</Level2>
\ No newline at end of file
diff --git a/test/runtime/samples/component-nested-deep/Level1.svelte b/test/runtime/samples/component-nested-deep/Level1.svelte
new file mode 100644
index 0000000000..1889fa2bd0
--- /dev/null
+++ b/test/runtime/samples/component-nested-deep/Level1.svelte
@@ -0,0 +1,8 @@
+<script>
+	import Level2 from './Level2.svelte';
+	import Level3 from './Level3.svelte';
+</script>
+
+<Level2>
+	<Level3 />
+</Level2>
\ No newline at end of file
diff --git a/test/runtime/samples/component-nested-deep/Level2.html b/test/runtime/samples/component-nested-deep/Level2.html
deleted file mode 100644
index 4b992b5cb3..0000000000
--- a/test/runtime/samples/component-nested-deep/Level2.html
+++ /dev/null
@@ -1,6 +0,0 @@
-<script>
-	import Level3 from './Level3.html';
-</script>
-
-<span>level 2</span>
-<slot></slot>
\ No newline at end of file
diff --git a/test/runtime/samples/component-nested-deep/Level2.svelte b/test/runtime/samples/component-nested-deep/Level2.svelte
new file mode 100644
index 0000000000..500c4c9887
--- /dev/null
+++ b/test/runtime/samples/component-nested-deep/Level2.svelte
@@ -0,0 +1,6 @@
+<script>
+	import Level3 from './Level3.svelte';
+</script>
+
+<span>level 2</span>
+<slot></slot>
\ No newline at end of file
diff --git a/test/runtime/samples/component-nested-deep/Level3.html b/test/runtime/samples/component-nested-deep/Level3.svelte
similarity index 100%
rename from test/runtime/samples/component-nested-deep/Level3.html
rename to test/runtime/samples/component-nested-deep/Level3.svelte
diff --git a/test/runtime/samples/component-nested-deep/main.html b/test/runtime/samples/component-nested-deep/main.html
deleted file mode 100644
index 57e4fc02b1..0000000000
--- a/test/runtime/samples/component-nested-deep/main.html
+++ /dev/null
@@ -1,7 +0,0 @@
-<script>
-	import Level1 from './Level1.html';
-
-	export let l1;
-</script>
-
-<Level1 bind:this={l1} />
\ No newline at end of file
diff --git a/test/runtime/samples/component-nested-deep/main.svelte b/test/runtime/samples/component-nested-deep/main.svelte
new file mode 100644
index 0000000000..a7007e27ea
--- /dev/null
+++ b/test/runtime/samples/component-nested-deep/main.svelte
@@ -0,0 +1,7 @@
+<script>
+	import Level1 from './Level1.svelte';
+
+	export let l1;
+</script>
+
+<Level1 bind:this={l1} />
\ No newline at end of file
diff --git a/test/runtime/samples/component-nested-deeper/Level1.html b/test/runtime/samples/component-nested-deeper/Level1.svelte
similarity index 74%
rename from test/runtime/samples/component-nested-deeper/Level1.html
rename to test/runtime/samples/component-nested-deeper/Level1.svelte
index 273e1b61c8..887782f121 100644
--- a/test/runtime/samples/component-nested-deeper/Level1.html
+++ b/test/runtime/samples/component-nested-deeper/Level1.svelte
@@ -1,6 +1,6 @@
 <script>
-	import Level2 from './Level2.html';
-	import Level3 from './Level3.html';
+	import Level2 from './Level2.svelte';
+	import Level3 from './Level3.svelte';
 	
 	export let values;
 </script>
diff --git a/test/runtime/samples/component-nested-deeper/Level2.html b/test/runtime/samples/component-nested-deeper/Level2.svelte
similarity index 100%
rename from test/runtime/samples/component-nested-deeper/Level2.html
rename to test/runtime/samples/component-nested-deeper/Level2.svelte
diff --git a/test/runtime/samples/component-nested-deeper/Level3.html b/test/runtime/samples/component-nested-deeper/Level3.svelte
similarity index 100%
rename from test/runtime/samples/component-nested-deeper/Level3.html
rename to test/runtime/samples/component-nested-deeper/Level3.svelte
diff --git a/test/runtime/samples/component-nested-deeper/main.html b/test/runtime/samples/component-nested-deeper/main.html
deleted file mode 100644
index 4c72ae6743..0000000000
--- a/test/runtime/samples/component-nested-deeper/main.html
+++ /dev/null
@@ -1,7 +0,0 @@
-<script>
-	import Level1 from './Level1.html';
-	
-	export let values;
-</script>
-
-<Level1 {values}/>
\ No newline at end of file
diff --git a/test/runtime/samples/component-nested-deeper/main.svelte b/test/runtime/samples/component-nested-deeper/main.svelte
new file mode 100644
index 0000000000..a1a6ff0de5
--- /dev/null
+++ b/test/runtime/samples/component-nested-deeper/main.svelte
@@ -0,0 +1,7 @@
+<script>
+	import Level1 from './Level1.svelte';
+	
+	export let values;
+</script>
+
+<Level1 {values}/>
\ No newline at end of file
diff --git a/test/runtime/samples/component-not-void/Link.html b/test/runtime/samples/component-not-void/Link.svelte
similarity index 100%
rename from test/runtime/samples/component-not-void/Link.html
rename to test/runtime/samples/component-not-void/Link.svelte
diff --git a/test/runtime/samples/component-not-void/main.html b/test/runtime/samples/component-not-void/main.html
deleted file mode 100644
index 0769c81092..0000000000
--- a/test/runtime/samples/component-not-void/main.html
+++ /dev/null
@@ -1,5 +0,0 @@
-<script>
-	import Link from './Link.html';
-</script>
-
-<Link>Hello</Link>
\ No newline at end of file
diff --git a/test/runtime/samples/component-not-void/main.svelte b/test/runtime/samples/component-not-void/main.svelte
new file mode 100644
index 0000000000..836777832b
--- /dev/null
+++ b/test/runtime/samples/component-not-void/main.svelte
@@ -0,0 +1,5 @@
+<script>
+	import Link from './Link.svelte';
+</script>
+
+<Link>Hello</Link>
\ No newline at end of file
diff --git a/test/runtime/samples/component-ref/Widget.html b/test/runtime/samples/component-ref/Widget.svelte
similarity index 100%
rename from test/runtime/samples/component-ref/Widget.html
rename to test/runtime/samples/component-ref/Widget.svelte
diff --git a/test/runtime/samples/component-ref/main.html b/test/runtime/samples/component-ref/main.svelte
similarity index 62%
rename from test/runtime/samples/component-ref/main.html
rename to test/runtime/samples/component-ref/main.svelte
index a91173c5af..1f51727c76 100644
--- a/test/runtime/samples/component-ref/main.html
+++ b/test/runtime/samples/component-ref/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Widget from './Widget.html';
+	import Widget from './Widget.svelte';
 	export let widget;
 </script>
 
diff --git a/test/runtime/samples/component-shorthand-import/Widget.html b/test/runtime/samples/component-shorthand-import/Widget.svelte
similarity index 100%
rename from test/runtime/samples/component-shorthand-import/Widget.html
rename to test/runtime/samples/component-shorthand-import/Widget.svelte
diff --git a/test/runtime/samples/component-shorthand-import/main.html b/test/runtime/samples/component-shorthand-import/main.html
deleted file mode 100644
index cbcde3f1ed..0000000000
--- a/test/runtime/samples/component-shorthand-import/main.html
+++ /dev/null
@@ -1,5 +0,0 @@
-<script>
-	import Widget from './Widget.html';
-</script>
-
-<Widget/>
\ No newline at end of file
diff --git a/test/runtime/samples/component-shorthand-import/main.svelte b/test/runtime/samples/component-shorthand-import/main.svelte
new file mode 100644
index 0000000000..0a9d5bba87
--- /dev/null
+++ b/test/runtime/samples/component-shorthand-import/main.svelte
@@ -0,0 +1,5 @@
+<script>
+	import Widget from './Widget.svelte';
+</script>
+
+<Widget/>
\ No newline at end of file
diff --git a/test/runtime/samples/component-slot-default/Nested.html b/test/runtime/samples/component-slot-default/Nested.svelte
similarity index 100%
rename from test/runtime/samples/component-slot-default/Nested.html
rename to test/runtime/samples/component-slot-default/Nested.svelte
diff --git a/test/runtime/samples/component-slot-default/main.html b/test/runtime/samples/component-slot-default/main.html
deleted file mode 100644
index 06a1f64cae..0000000000
--- a/test/runtime/samples/component-slot-default/main.html
+++ /dev/null
@@ -1,7 +0,0 @@
-<script>
-	import Nested from './Nested.html';
-</script>
-
-<Nested>
-	Hello
-</Nested>
\ No newline at end of file
diff --git a/test/runtime/samples/component-slot-default/main.svelte b/test/runtime/samples/component-slot-default/main.svelte
new file mode 100644
index 0000000000..1e1ea8daa8
--- /dev/null
+++ b/test/runtime/samples/component-slot-default/main.svelte
@@ -0,0 +1,7 @@
+<script>
+	import Nested from './Nested.svelte';
+</script>
+
+<Nested>
+	Hello
+</Nested>
\ No newline at end of file
diff --git a/test/runtime/samples/component-slot-dynamic/Nested.html b/test/runtime/samples/component-slot-dynamic/Nested.svelte
similarity index 100%
rename from test/runtime/samples/component-slot-dynamic/Nested.html
rename to test/runtime/samples/component-slot-dynamic/Nested.svelte
diff --git a/test/runtime/samples/component-slot-dynamic/main.html b/test/runtime/samples/component-slot-dynamic/main.svelte
similarity index 67%
rename from test/runtime/samples/component-slot-dynamic/main.html
rename to test/runtime/samples/component-slot-dynamic/main.svelte
index ad952b38bb..8eb876444a 100644
--- a/test/runtime/samples/component-slot-dynamic/main.html
+++ b/test/runtime/samples/component-slot-dynamic/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Nested from './Nested.html';
+	import Nested from './Nested.svelte';
 
 	export let nested;
 </script>
diff --git a/test/runtime/samples/component-slot-each-block/Nested.html b/test/runtime/samples/component-slot-each-block/Nested.svelte
similarity index 100%
rename from test/runtime/samples/component-slot-each-block/Nested.html
rename to test/runtime/samples/component-slot-each-block/Nested.svelte
diff --git a/test/runtime/samples/component-slot-each-block/main.html b/test/runtime/samples/component-slot-each-block/main.svelte
similarity index 69%
rename from test/runtime/samples/component-slot-each-block/main.html
rename to test/runtime/samples/component-slot-each-block/main.svelte
index 911eb5c1ae..986c5c40e1 100644
--- a/test/runtime/samples/component-slot-each-block/main.html
+++ b/test/runtime/samples/component-slot-each-block/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Nested from './Nested.html';
+	import Nested from './Nested.svelte';
 
 	export let things;
 </script>
diff --git a/test/runtime/samples/component-slot-empty/Nested.html b/test/runtime/samples/component-slot-empty/Nested.svelte
similarity index 100%
rename from test/runtime/samples/component-slot-empty/Nested.html
rename to test/runtime/samples/component-slot-empty/Nested.svelte
diff --git a/test/runtime/samples/component-slot-empty/main.html b/test/runtime/samples/component-slot-empty/main.html
deleted file mode 100644
index 3d76b0a696..0000000000
--- a/test/runtime/samples/component-slot-empty/main.html
+++ /dev/null
@@ -1,6 +0,0 @@
-<script>
-	import Nested from './Nested.html';
-</script>
-
-<Nested>
-</Nested>
\ No newline at end of file
diff --git a/test/runtime/samples/component-slot-empty/main.svelte b/test/runtime/samples/component-slot-empty/main.svelte
new file mode 100644
index 0000000000..619060e4cb
--- /dev/null
+++ b/test/runtime/samples/component-slot-empty/main.svelte
@@ -0,0 +1,6 @@
+<script>
+	import Nested from './Nested.svelte';
+</script>
+
+<Nested>
+</Nested>
\ No newline at end of file
diff --git a/test/runtime/samples/component-slot-fallback/Nested.html b/test/runtime/samples/component-slot-fallback/Nested.svelte
similarity index 100%
rename from test/runtime/samples/component-slot-fallback/Nested.html
rename to test/runtime/samples/component-slot-fallback/Nested.svelte
diff --git a/test/runtime/samples/component-slot-fallback/main.html b/test/runtime/samples/component-slot-fallback/main.svelte
similarity index 51%
rename from test/runtime/samples/component-slot-fallback/main.html
rename to test/runtime/samples/component-slot-fallback/main.svelte
index f4d609216c..0bdb6f8b1d 100644
--- a/test/runtime/samples/component-slot-fallback/main.html
+++ b/test/runtime/samples/component-slot-fallback/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Nested from './Nested.html';
+	import Nested from './Nested.svelte';
 </script>
 
 <Nested>
diff --git a/test/runtime/samples/component-slot-if-block-before-node/Nested.html b/test/runtime/samples/component-slot-if-block-before-node/Nested.svelte
similarity index 100%
rename from test/runtime/samples/component-slot-if-block-before-node/Nested.html
rename to test/runtime/samples/component-slot-if-block-before-node/Nested.svelte
diff --git a/test/runtime/samples/component-slot-if-block/main.html b/test/runtime/samples/component-slot-if-block-before-node/main.svelte
similarity index 69%
rename from test/runtime/samples/component-slot-if-block/main.html
rename to test/runtime/samples/component-slot-if-block-before-node/main.svelte
index 2b0405a471..6e51f27649 100644
--- a/test/runtime/samples/component-slot-if-block/main.html
+++ b/test/runtime/samples/component-slot-if-block-before-node/main.svelte
@@ -1,13 +1,13 @@
 <script>
-	import Nested from './Nested.html';
+	import Nested from './Nested.svelte';
 
 	export let foo;
 </script>
 
 <Nested>
-	<p>unconditional</p>
-
 	{#if foo}
 		<p>conditional</p>
 	{/if}
+
+	<p>unconditional</p>
 </Nested>
\ No newline at end of file
diff --git a/test/runtime/samples/component-slot-if-block/Nested.html b/test/runtime/samples/component-slot-if-block/Nested.svelte
similarity index 100%
rename from test/runtime/samples/component-slot-if-block/Nested.html
rename to test/runtime/samples/component-slot-if-block/Nested.svelte
diff --git a/test/runtime/samples/component-slot-if-block-before-node/main.html b/test/runtime/samples/component-slot-if-block/main.svelte
similarity index 69%
rename from test/runtime/samples/component-slot-if-block-before-node/main.html
rename to test/runtime/samples/component-slot-if-block/main.svelte
index 01ea1e8455..465da320a9 100644
--- a/test/runtime/samples/component-slot-if-block-before-node/main.html
+++ b/test/runtime/samples/component-slot-if-block/main.svelte
@@ -1,13 +1,13 @@
 <script>
-	import Nested from './Nested.html';
+	import Nested from './Nested.svelte';
 
 	export let foo;
 </script>
 
 <Nested>
+	<p>unconditional</p>
+
 	{#if foo}
 		<p>conditional</p>
 	{/if}
-
-	<p>unconditional</p>
 </Nested>
\ No newline at end of file
diff --git a/test/runtime/samples/component-slot-if-else-block-before-node/Nested.html b/test/runtime/samples/component-slot-if-else-block-before-node/Nested.svelte
similarity index 100%
rename from test/runtime/samples/component-slot-if-else-block-before-node/Nested.html
rename to test/runtime/samples/component-slot-if-else-block-before-node/Nested.svelte
diff --git a/test/runtime/samples/component-slot-if-else-block-before-node/main.html b/test/runtime/samples/component-slot-if-else-block-before-node/main.svelte
similarity index 74%
rename from test/runtime/samples/component-slot-if-else-block-before-node/main.html
rename to test/runtime/samples/component-slot-if-else-block-before-node/main.svelte
index 684497b98a..0b24f77b16 100644
--- a/test/runtime/samples/component-slot-if-else-block-before-node/main.html
+++ b/test/runtime/samples/component-slot-if-else-block-before-node/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Nested from './Nested.html';
+	import Nested from './Nested.svelte';
 
 	export let enabled;
 </script>
diff --git a/test/runtime/samples/component-slot-let-aliased/Nested.html b/test/runtime/samples/component-slot-let-aliased/Nested.svelte
similarity index 100%
rename from test/runtime/samples/component-slot-let-aliased/Nested.html
rename to test/runtime/samples/component-slot-let-aliased/Nested.svelte
diff --git a/test/runtime/samples/component-slot-let-aliased/main.html b/test/runtime/samples/component-slot-let-aliased/main.svelte
similarity index 65%
rename from test/runtime/samples/component-slot-let-aliased/main.html
rename to test/runtime/samples/component-slot-let-aliased/main.svelte
index 1acb7fbcdc..468a58face 100644
--- a/test/runtime/samples/component-slot-let-aliased/main.html
+++ b/test/runtime/samples/component-slot-let-aliased/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Nested from './Nested.html';
+	import Nested from './Nested.svelte';
 
 	export let things;
 </script>
diff --git a/test/runtime/samples/component-slot-let-b/Nested.html b/test/runtime/samples/component-slot-let-b/Nested.svelte
similarity index 100%
rename from test/runtime/samples/component-slot-let-b/Nested.html
rename to test/runtime/samples/component-slot-let-b/Nested.svelte
diff --git a/test/runtime/samples/component-slot-let-b/main.html b/test/runtime/samples/component-slot-let-b/main.svelte
similarity index 55%
rename from test/runtime/samples/component-slot-let-b/main.html
rename to test/runtime/samples/component-slot-let-b/main.svelte
index b4fd5f54c6..4acec62b21 100644
--- a/test/runtime/samples/component-slot-let-b/main.html
+++ b/test/runtime/samples/component-slot-let-b/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Nested from './Nested.html';
+	import Nested from './Nested.svelte';
 </script>
 
 <Nested let:count>
diff --git a/test/runtime/samples/component-slot-let-c/Nested.html b/test/runtime/samples/component-slot-let-c/Nested.svelte
similarity index 100%
rename from test/runtime/samples/component-slot-let-c/Nested.html
rename to test/runtime/samples/component-slot-let-c/Nested.svelte
diff --git a/test/runtime/samples/component-slot-let-c/main.html b/test/runtime/samples/component-slot-let-c/main.svelte
similarity index 60%
rename from test/runtime/samples/component-slot-let-c/main.html
rename to test/runtime/samples/component-slot-let-c/main.svelte
index b834fd8790..b594964303 100644
--- a/test/runtime/samples/component-slot-let-c/main.html
+++ b/test/runtime/samples/component-slot-let-c/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Nested from './Nested.html';
+	import Nested from './Nested.svelte';
 </script>
 
 <Nested let:c let:count>
diff --git a/test/runtime/samples/component-slot-let-destructured/Nested.html b/test/runtime/samples/component-slot-let-destructured/Nested.svelte
similarity index 100%
rename from test/runtime/samples/component-slot-let-destructured/Nested.html
rename to test/runtime/samples/component-slot-let-destructured/Nested.svelte
diff --git a/test/runtime/samples/component-slot-let-destructured/main.html b/test/runtime/samples/component-slot-let-destructured/main.svelte
similarity index 67%
rename from test/runtime/samples/component-slot-let-destructured/main.html
rename to test/runtime/samples/component-slot-let-destructured/main.svelte
index 488fd463de..1ee93bf105 100644
--- a/test/runtime/samples/component-slot-let-destructured/main.html
+++ b/test/runtime/samples/component-slot-let-destructured/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Nested from './Nested.html';
+	import Nested from './Nested.svelte';
 
 	export let things;
 </script>
diff --git a/test/runtime/samples/component-slot-let-named/Nested.html b/test/runtime/samples/component-slot-let-named/Nested.svelte
similarity index 100%
rename from test/runtime/samples/component-slot-let-named/Nested.html
rename to test/runtime/samples/component-slot-let-named/Nested.svelte
diff --git a/test/runtime/samples/component-slot-let-named/main.html b/test/runtime/samples/component-slot-let-named/main.svelte
similarity index 71%
rename from test/runtime/samples/component-slot-let-named/main.html
rename to test/runtime/samples/component-slot-let-named/main.svelte
index 1c3d3365c7..f9e9e3a10f 100644
--- a/test/runtime/samples/component-slot-let-named/main.html
+++ b/test/runtime/samples/component-slot-let-named/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Nested from './Nested.html';
+	import Nested from './Nested.svelte';
 
 	export let things;
 </script>
diff --git a/test/runtime/samples/component-slot-let-static/Nested.html b/test/runtime/samples/component-slot-let-static/Nested.svelte
similarity index 100%
rename from test/runtime/samples/component-slot-let-static/Nested.html
rename to test/runtime/samples/component-slot-let-static/Nested.svelte
diff --git a/test/runtime/samples/component-slot-let-static/main.html b/test/runtime/samples/component-slot-let-static/main.svelte
similarity index 53%
rename from test/runtime/samples/component-slot-let-static/main.html
rename to test/runtime/samples/component-slot-let-static/main.svelte
index 6e91b0d026..3eeaba976e 100644
--- a/test/runtime/samples/component-slot-let-static/main.html
+++ b/test/runtime/samples/component-slot-let-static/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Nested from './Nested.html';
+	import Nested from './Nested.svelte';
 </script>
 
 <Nested let:value>
diff --git a/test/runtime/samples/component-slot-let/Nested.html b/test/runtime/samples/component-slot-let/Nested.svelte
similarity index 100%
rename from test/runtime/samples/component-slot-let/Nested.html
rename to test/runtime/samples/component-slot-let/Nested.svelte
diff --git a/test/runtime/samples/component-slot-let/main.html b/test/runtime/samples/component-slot-let/main.svelte
similarity index 65%
rename from test/runtime/samples/component-slot-let/main.html
rename to test/runtime/samples/component-slot-let/main.svelte
index 76d491389f..d00bb8e41e 100644
--- a/test/runtime/samples/component-slot-let/main.html
+++ b/test/runtime/samples/component-slot-let/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Nested from './Nested.html';
+	import Nested from './Nested.svelte';
 
 	export let things;
 </script>
diff --git a/test/runtime/samples/component-slot-name-with-hyphen/Nested.html b/test/runtime/samples/component-slot-name-with-hyphen/Nested.svelte
similarity index 100%
rename from test/runtime/samples/component-slot-name-with-hyphen/Nested.html
rename to test/runtime/samples/component-slot-name-with-hyphen/Nested.svelte
diff --git a/test/runtime/samples/component-slot-name-with-hyphen/main.html b/test/runtime/samples/component-slot-name-with-hyphen/main.svelte
similarity index 54%
rename from test/runtime/samples/component-slot-name-with-hyphen/main.html
rename to test/runtime/samples/component-slot-name-with-hyphen/main.svelte
index a77e524f89..13a65b2196 100644
--- a/test/runtime/samples/component-slot-name-with-hyphen/main.html
+++ b/test/runtime/samples/component-slot-name-with-hyphen/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Nested from './Nested.html';
+	import Nested from './Nested.svelte';
 </script>
 
 <Nested>
diff --git a/test/runtime/samples/component-slot-named/Nested.html b/test/runtime/samples/component-slot-named/Nested.svelte
similarity index 100%
rename from test/runtime/samples/component-slot-named/Nested.html
rename to test/runtime/samples/component-slot-named/Nested.svelte
diff --git a/test/runtime/samples/component-slot-named/main.html b/test/runtime/samples/component-slot-named/main.svelte
similarity index 63%
rename from test/runtime/samples/component-slot-named/main.html
rename to test/runtime/samples/component-slot-named/main.svelte
index 627c3ab7e0..e25587c1e5 100644
--- a/test/runtime/samples/component-slot-named/main.html
+++ b/test/runtime/samples/component-slot-named/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Nested from './Nested.html';
+	import Nested from './Nested.svelte';
 </script>
 
 <Nested>
diff --git a/test/runtime/samples/component-slot-nested-component/Inner.html b/test/runtime/samples/component-slot-nested-component/Inner.svelte
similarity index 100%
rename from test/runtime/samples/component-slot-nested-component/Inner.html
rename to test/runtime/samples/component-slot-nested-component/Inner.svelte
diff --git a/test/runtime/samples/component-slot-nested-component/Outer.html b/test/runtime/samples/component-slot-nested-component/Outer.svelte
similarity index 100%
rename from test/runtime/samples/component-slot-nested-component/Outer.html
rename to test/runtime/samples/component-slot-nested-component/Outer.svelte
diff --git a/test/runtime/samples/component-slot-nested-component/main.html b/test/runtime/samples/component-slot-nested-component/main.html
deleted file mode 100644
index d86e58bb70..0000000000
--- a/test/runtime/samples/component-slot-nested-component/main.html
+++ /dev/null
@@ -1,8 +0,0 @@
-<script>
-	import Outer from './Outer.html';
-	import Inner from './Inner.html';
-</script>
-
-<Outer>
-	<Inner>foo</Inner>
-</Outer>
\ No newline at end of file
diff --git a/test/runtime/samples/component-slot-nested-component/main.svelte b/test/runtime/samples/component-slot-nested-component/main.svelte
new file mode 100644
index 0000000000..45c6d437b6
--- /dev/null
+++ b/test/runtime/samples/component-slot-nested-component/main.svelte
@@ -0,0 +1,8 @@
+<script>
+	import Outer from './Outer.svelte';
+	import Inner from './Inner.svelte';
+</script>
+
+<Outer>
+	<Inner>foo</Inner>
+</Outer>
\ No newline at end of file
diff --git a/test/runtime/samples/component-slot-nested/Nested.html b/test/runtime/samples/component-slot-nested/Nested.svelte
similarity index 100%
rename from test/runtime/samples/component-slot-nested/Nested.html
rename to test/runtime/samples/component-slot-nested/Nested.svelte
diff --git a/test/runtime/samples/component-slot-nested/main.html b/test/runtime/samples/component-slot-nested/main.svelte
similarity index 52%
rename from test/runtime/samples/component-slot-nested/main.html
rename to test/runtime/samples/component-slot-nested/main.svelte
index a109ec9c06..982a918709 100644
--- a/test/runtime/samples/component-slot-nested/main.html
+++ b/test/runtime/samples/component-slot-nested/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Nested from './Nested.html';
+	import Nested from './Nested.svelte';
 </script>
 
 <Nested>
diff --git a/test/runtime/samples/component-slot-used-with-default-event/Nested.html b/test/runtime/samples/component-slot-used-with-default-event/Nested.svelte
similarity index 100%
rename from test/runtime/samples/component-slot-used-with-default-event/Nested.html
rename to test/runtime/samples/component-slot-used-with-default-event/Nested.svelte
diff --git a/test/runtime/samples/component-slot-used-with-default-event/main.html b/test/runtime/samples/component-slot-used-with-default-event/main.html
deleted file mode 100644
index 06a1f64cae..0000000000
--- a/test/runtime/samples/component-slot-used-with-default-event/main.html
+++ /dev/null
@@ -1,7 +0,0 @@
-<script>
-	import Nested from './Nested.html';
-</script>
-
-<Nested>
-	Hello
-</Nested>
\ No newline at end of file
diff --git a/test/runtime/samples/component-slot-used-with-default-event/main.svelte b/test/runtime/samples/component-slot-used-with-default-event/main.svelte
new file mode 100644
index 0000000000..1e1ea8daa8
--- /dev/null
+++ b/test/runtime/samples/component-slot-used-with-default-event/main.svelte
@@ -0,0 +1,7 @@
+<script>
+	import Nested from './Nested.svelte';
+</script>
+
+<Nested>
+	Hello
+</Nested>
\ No newline at end of file
diff --git a/test/runtime/samples/component-static-at-symbol/Email.html b/test/runtime/samples/component-static-at-symbol/Email.svelte
similarity index 100%
rename from test/runtime/samples/component-static-at-symbol/Email.html
rename to test/runtime/samples/component-static-at-symbol/Email.svelte
diff --git a/test/runtime/samples/component-static-at-symbol/main.html b/test/runtime/samples/component-static-at-symbol/main.html
deleted file mode 100644
index 275b922f6a..0000000000
--- a/test/runtime/samples/component-static-at-symbol/main.html
+++ /dev/null
@@ -1,5 +0,0 @@
-<script>
-	import Email from './Email.html';
-</script>
-
-<Email address='hello@example.com'/>
\ No newline at end of file
diff --git a/test/runtime/samples/component-static-at-symbol/main.svelte b/test/runtime/samples/component-static-at-symbol/main.svelte
new file mode 100644
index 0000000000..39f82ffd25
--- /dev/null
+++ b/test/runtime/samples/component-static-at-symbol/main.svelte
@@ -0,0 +1,5 @@
+<script>
+	import Email from './Email.svelte';
+</script>
+
+<Email address='hello@example.com'/>
\ No newline at end of file
diff --git a/test/runtime/samples/component-template-inline-mutation/Widget.html b/test/runtime/samples/component-template-inline-mutation/Widget.svelte
similarity index 100%
rename from test/runtime/samples/component-template-inline-mutation/Widget.html
rename to test/runtime/samples/component-template-inline-mutation/Widget.svelte
diff --git a/test/runtime/samples/component-template-inline-mutation/main.html b/test/runtime/samples/component-template-inline-mutation/main.html
deleted file mode 100644
index f094aef743..0000000000
--- a/test/runtime/samples/component-template-inline-mutation/main.html
+++ /dev/null
@@ -1,6 +0,0 @@
-<script>
-	import Widget from './Widget.html';
-</script>
-
-<Widget />
-<Widget />
\ No newline at end of file
diff --git a/test/runtime/samples/component-template-inline-mutation/main.svelte b/test/runtime/samples/component-template-inline-mutation/main.svelte
new file mode 100644
index 0000000000..b77462c690
--- /dev/null
+++ b/test/runtime/samples/component-template-inline-mutation/main.svelte
@@ -0,0 +1,6 @@
+<script>
+	import Widget from './Widget.svelte';
+</script>
+
+<Widget />
+<Widget />
\ No newline at end of file
diff --git a/test/runtime/samples/component-yield-follows-element/Foo.html b/test/runtime/samples/component-yield-follows-element/Foo.svelte
similarity index 100%
rename from test/runtime/samples/component-yield-follows-element/Foo.html
rename to test/runtime/samples/component-yield-follows-element/Foo.svelte
diff --git a/test/runtime/samples/component-yield-follows-element/main.html b/test/runtime/samples/component-yield-follows-element/main.html
deleted file mode 100644
index b362e9a410..0000000000
--- a/test/runtime/samples/component-yield-follows-element/main.html
+++ /dev/null
@@ -1,5 +0,0 @@
-<script>
-	import Foo from './Foo.html';
-</script>
-
-<Foo>test</Foo>
\ No newline at end of file
diff --git a/test/runtime/samples/component-yield-follows-element/main.svelte b/test/runtime/samples/component-yield-follows-element/main.svelte
new file mode 100644
index 0000000000..3a43b58231
--- /dev/null
+++ b/test/runtime/samples/component-yield-follows-element/main.svelte
@@ -0,0 +1,5 @@
+<script>
+	import Foo from './Foo.svelte';
+</script>
+
+<Foo>test</Foo>
\ No newline at end of file
diff --git a/test/runtime/samples/component-yield-if/Widget.html b/test/runtime/samples/component-yield-if/Widget.svelte
similarity index 100%
rename from test/runtime/samples/component-yield-if/Widget.html
rename to test/runtime/samples/component-yield-if/Widget.svelte
diff --git a/test/runtime/samples/component-yield-if/main.html b/test/runtime/samples/component-yield-if/main.svelte
similarity index 72%
rename from test/runtime/samples/component-yield-if/main.html
rename to test/runtime/samples/component-yield-if/main.svelte
index 768993e064..4e02155a8b 100644
--- a/test/runtime/samples/component-yield-if/main.html
+++ b/test/runtime/samples/component-yield-if/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Widget from './Widget.html';
+	import Widget from './Widget.svelte';
 
 	export let widget;
 	export let data = "Hello";
diff --git a/test/runtime/samples/component-yield-multiple-in-each/Widget.html b/test/runtime/samples/component-yield-multiple-in-each/Widget.svelte
similarity index 100%
rename from test/runtime/samples/component-yield-multiple-in-each/Widget.html
rename to test/runtime/samples/component-yield-multiple-in-each/Widget.svelte
diff --git a/test/runtime/samples/component-yield-multiple-in-each/main.html b/test/runtime/samples/component-yield-multiple-in-each/main.svelte
similarity index 74%
rename from test/runtime/samples/component-yield-multiple-in-each/main.html
rename to test/runtime/samples/component-yield-multiple-in-each/main.svelte
index 5f2027ee98..d41424e9b7 100644
--- a/test/runtime/samples/component-yield-multiple-in-each/main.html
+++ b/test/runtime/samples/component-yield-multiple-in-each/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Widget from './Widget.html';
+	import Widget from './Widget.svelte';
 
 	export let people = [ 'Alice', 'Bob', 'Charles' ];
 </script>
diff --git a/test/runtime/samples/component-yield-multiple-in-if/Widget.html b/test/runtime/samples/component-yield-multiple-in-if/Widget.svelte
similarity index 100%
rename from test/runtime/samples/component-yield-multiple-in-if/Widget.html
rename to test/runtime/samples/component-yield-multiple-in-if/Widget.svelte
diff --git a/test/runtime/samples/component-yield-multiple-in-if/main.html b/test/runtime/samples/component-yield-multiple-in-if/main.svelte
similarity index 75%
rename from test/runtime/samples/component-yield-multiple-in-if/main.html
rename to test/runtime/samples/component-yield-multiple-in-if/main.svelte
index 53eba749d6..db518183b5 100644
--- a/test/runtime/samples/component-yield-multiple-in-if/main.html
+++ b/test/runtime/samples/component-yield-multiple-in-if/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Widget from './Widget.html';
+	import Widget from './Widget.svelte';
 
 	export let arriving = true;
 </script>
diff --git a/test/runtime/samples/component-yield-nested-if/Inner.html b/test/runtime/samples/component-yield-nested-if/Inner.svelte
similarity index 100%
rename from test/runtime/samples/component-yield-nested-if/Inner.html
rename to test/runtime/samples/component-yield-nested-if/Inner.svelte
diff --git a/test/runtime/samples/component-yield-nested-if/Outer.html b/test/runtime/samples/component-yield-nested-if/Outer.svelte
similarity index 100%
rename from test/runtime/samples/component-yield-nested-if/Outer.html
rename to test/runtime/samples/component-yield-nested-if/Outer.svelte
diff --git a/test/runtime/samples/component-yield-nested-if/main.html b/test/runtime/samples/component-yield-nested-if/main.html
deleted file mode 100644
index 98c27812e6..0000000000
--- a/test/runtime/samples/component-yield-nested-if/main.html
+++ /dev/null
@@ -1,11 +0,0 @@
-<script>
-	import Outer from './Outer.html';
-	import Inner from './Inner.html';
-
-	export let foo = true;
-</script>
-
-<Outer {foo}>
-	One
-	<Inner/>
-</Outer>
\ No newline at end of file
diff --git a/test/runtime/samples/component-yield-nested-if/main.svelte b/test/runtime/samples/component-yield-nested-if/main.svelte
new file mode 100644
index 0000000000..2107a21ed4
--- /dev/null
+++ b/test/runtime/samples/component-yield-nested-if/main.svelte
@@ -0,0 +1,11 @@
+<script>
+	import Outer from './Outer.svelte';
+	import Inner from './Inner.svelte';
+
+	export let foo = true;
+</script>
+
+<Outer {foo}>
+	One
+	<Inner/>
+</Outer>
\ No newline at end of file
diff --git a/test/runtime/samples/component-yield-parent/Widget.html b/test/runtime/samples/component-yield-parent/Widget.svelte
similarity index 100%
rename from test/runtime/samples/component-yield-parent/Widget.html
rename to test/runtime/samples/component-yield-parent/Widget.svelte
diff --git a/test/runtime/samples/component-yield-parent/main.html b/test/runtime/samples/component-yield-parent/main.svelte
similarity index 64%
rename from test/runtime/samples/component-yield-parent/main.html
rename to test/runtime/samples/component-yield-parent/main.svelte
index b36dbc1b14..8de37236ae 100644
--- a/test/runtime/samples/component-yield-parent/main.html
+++ b/test/runtime/samples/component-yield-parent/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Widget from './Widget.html'
+	import Widget from './Widget.svelte'
 	export let data = "Hello";
 </script>
 
diff --git a/test/runtime/samples/component-yield-placement/Modal.html b/test/runtime/samples/component-yield-placement/Modal.svelte
similarity index 100%
rename from test/runtime/samples/component-yield-placement/Modal.html
rename to test/runtime/samples/component-yield-placement/Modal.svelte
diff --git a/test/runtime/samples/component-yield-placement/main.html b/test/runtime/samples/component-yield-placement/main.svelte
similarity index 83%
rename from test/runtime/samples/component-yield-placement/main.html
rename to test/runtime/samples/component-yield-placement/main.svelte
index cc5bfd73ed..ee1a1221eb 100644
--- a/test/runtime/samples/component-yield-placement/main.html
+++ b/test/runtime/samples/component-yield-placement/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Modal from './Modal.html';
+	import Modal from './Modal.svelte';
 
 	export let showModal;
 </script>
diff --git a/test/runtime/samples/component-yield-static/Widget.html b/test/runtime/samples/component-yield-static/Widget.svelte
similarity index 100%
rename from test/runtime/samples/component-yield-static/Widget.html
rename to test/runtime/samples/component-yield-static/Widget.svelte
diff --git a/test/runtime/samples/component-yield-static/main.html b/test/runtime/samples/component-yield-static/main.html
deleted file mode 100644
index 9d5807872d..0000000000
--- a/test/runtime/samples/component-yield-static/main.html
+++ /dev/null
@@ -1,7 +0,0 @@
-<script>
-	import Widget from './Widget.html';
-
-	export let name = '';
-</script>
-
-<Widget>Hello</Widget> {name}
\ No newline at end of file
diff --git a/test/runtime/samples/component-yield-static/main.svelte b/test/runtime/samples/component-yield-static/main.svelte
new file mode 100644
index 0000000000..3e99a8baa9
--- /dev/null
+++ b/test/runtime/samples/component-yield-static/main.svelte
@@ -0,0 +1,7 @@
+<script>
+	import Widget from './Widget.svelte';
+
+	export let name = '';
+</script>
+
+<Widget>Hello</Widget> {name}
\ No newline at end of file
diff --git a/test/runtime/samples/component-yield/main.html b/test/runtime/samples/component-yield/main.svelte
similarity index 100%
rename from test/runtime/samples/component-yield/main.html
rename to test/runtime/samples/component-yield/main.svelte
diff --git a/test/runtime/samples/component/Widget.html b/test/runtime/samples/component/Widget.svelte
similarity index 100%
rename from test/runtime/samples/component/Widget.html
rename to test/runtime/samples/component/Widget.svelte
diff --git a/test/runtime/samples/component/main.html b/test/runtime/samples/component/main.html
deleted file mode 100644
index 1bd0073a0e..0000000000
--- a/test/runtime/samples/component/main.html
+++ /dev/null
@@ -1,7 +0,0 @@
-<script>
-	import Widget from './Widget.html';
-</script>
-
-<div>
-	<Widget/>
-</div>
\ No newline at end of file
diff --git a/test/runtime/samples/component/main.svelte b/test/runtime/samples/component/main.svelte
new file mode 100644
index 0000000000..fb2f332507
--- /dev/null
+++ b/test/runtime/samples/component/main.svelte
@@ -0,0 +1,7 @@
+<script>
+	import Widget from './Widget.svelte';
+</script>
+
+<div>
+	<Widget/>
+</div>
\ No newline at end of file
diff --git a/test/runtime/samples/context-api/Tab.html b/test/runtime/samples/context-api/Tab.svelte
similarity index 87%
rename from test/runtime/samples/context-api/Tab.html
rename to test/runtime/samples/context-api/Tab.svelte
index 2f9793aed8..af3f002521 100644
--- a/test/runtime/samples/context-api/Tab.html
+++ b/test/runtime/samples/context-api/Tab.svelte
@@ -1,6 +1,6 @@
 <script>
 	import { getContext, onDestroy } from 'svelte';
-	import { TABS } from './Tabs.html';
+	import { TABS } from './Tabs.svelte';
 
 	const tab = {};
 	const { registerTab, unregisterTab, selectTab, selectedTab } = getContext(TABS);
diff --git a/test/runtime/samples/context-api/TabList.html b/test/runtime/samples/context-api/TabList.svelte
similarity index 100%
rename from test/runtime/samples/context-api/TabList.html
rename to test/runtime/samples/context-api/TabList.svelte
diff --git a/test/runtime/samples/context-api/TabPanel.html b/test/runtime/samples/context-api/TabPanel.svelte
similarity index 86%
rename from test/runtime/samples/context-api/TabPanel.html
rename to test/runtime/samples/context-api/TabPanel.svelte
index e15dfca021..a506ba9c07 100644
--- a/test/runtime/samples/context-api/TabPanel.html
+++ b/test/runtime/samples/context-api/TabPanel.svelte
@@ -1,6 +1,6 @@
 <script>
 	import { getContext, onDestroy } from 'svelte';
-	import { TABS } from './Tabs.html';
+	import { TABS } from './Tabs.svelte';
 
 	const panel = {};
 	const { registerPanel, unregisterPanel, selectedPanel } = getContext(TABS);
diff --git a/test/runtime/samples/context-api/Tabs.html b/test/runtime/samples/context-api/Tabs.svelte
similarity index 100%
rename from test/runtime/samples/context-api/Tabs.html
rename to test/runtime/samples/context-api/Tabs.svelte
diff --git a/test/runtime/samples/context-api/main.html b/test/runtime/samples/context-api/main.svelte
similarity index 68%
rename from test/runtime/samples/context-api/main.html
rename to test/runtime/samples/context-api/main.svelte
index ef3ee996d5..5d569a2125 100644
--- a/test/runtime/samples/context-api/main.html
+++ b/test/runtime/samples/context-api/main.svelte
@@ -1,8 +1,8 @@
 <script>
-	import Tabs from './Tabs.html';
-	import TabList from './TabList.html';
-	import Tab from './Tab.html';
-	import TabPanel from './TabPanel.html';
+	import Tabs from './Tabs.svelte';
+	import TabList from './TabList.svelte';
+	import Tab from './Tab.svelte';
+	import TabPanel from './TabPanel.svelte';
 
 	export let show_medium = false;
 </script>
diff --git a/test/runtime/samples/css-comments/main.html b/test/runtime/samples/css-comments/main.svelte
similarity index 100%
rename from test/runtime/samples/css-comments/main.html
rename to test/runtime/samples/css-comments/main.svelte
diff --git a/test/runtime/samples/css-false/Widget.html b/test/runtime/samples/css-false/Widget.svelte
similarity index 100%
rename from test/runtime/samples/css-false/Widget.html
rename to test/runtime/samples/css-false/Widget.svelte
diff --git a/test/runtime/samples/css-false/main.html b/test/runtime/samples/css-false/main.html
deleted file mode 100644
index dbbc5c325b..0000000000
--- a/test/runtime/samples/css-false/main.html
+++ /dev/null
@@ -1,6 +0,0 @@
-<script>
-	import Widget from './Widget.html';
-</script>
-
-<p>control</p>
-<Widget/>
\ No newline at end of file
diff --git a/test/runtime/samples/css-false/main.svelte b/test/runtime/samples/css-false/main.svelte
new file mode 100644
index 0000000000..5129d127ba
--- /dev/null
+++ b/test/runtime/samples/css-false/main.svelte
@@ -0,0 +1,6 @@
+<script>
+	import Widget from './Widget.svelte';
+</script>
+
+<p>control</p>
+<Widget/>
\ No newline at end of file
diff --git a/test/runtime/samples/css-space-in-attribute/Widget.html b/test/runtime/samples/css-space-in-attribute/Widget.svelte
similarity index 100%
rename from test/runtime/samples/css-space-in-attribute/Widget.html
rename to test/runtime/samples/css-space-in-attribute/Widget.svelte
diff --git a/test/runtime/samples/css-space-in-attribute/main.html b/test/runtime/samples/css-space-in-attribute/main.svelte
similarity index 51%
rename from test/runtime/samples/css-space-in-attribute/main.html
rename to test/runtime/samples/css-space-in-attribute/main.svelte
index 93bec897f3..e23e6c4e40 100644
--- a/test/runtime/samples/css-space-in-attribute/main.html
+++ b/test/runtime/samples/css-space-in-attribute/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Widget from './Widget.html';
+	import Widget from './Widget.svelte';
 </script>
 
 <p class='foo bar'>control</p>
diff --git a/test/runtime/samples/css/Widget.html b/test/runtime/samples/css/Widget.svelte
similarity index 100%
rename from test/runtime/samples/css/Widget.html
rename to test/runtime/samples/css/Widget.svelte
diff --git a/test/runtime/samples/css/main.html b/test/runtime/samples/css/main.html
deleted file mode 100644
index dbbc5c325b..0000000000
--- a/test/runtime/samples/css/main.html
+++ /dev/null
@@ -1,6 +0,0 @@
-<script>
-	import Widget from './Widget.html';
-</script>
-
-<p>control</p>
-<Widget/>
\ No newline at end of file
diff --git a/test/runtime/samples/css/main.svelte b/test/runtime/samples/css/main.svelte
new file mode 100644
index 0000000000..5129d127ba
--- /dev/null
+++ b/test/runtime/samples/css/main.svelte
@@ -0,0 +1,6 @@
+<script>
+	import Widget from './Widget.svelte';
+</script>
+
+<p>control</p>
+<Widget/>
\ No newline at end of file
diff --git a/test/runtime/samples/custom-method/main.html b/test/runtime/samples/custom-method/main.svelte
similarity index 100%
rename from test/runtime/samples/custom-method/main.html
rename to test/runtime/samples/custom-method/main.svelte
diff --git a/test/runtime/samples/deconflict-builtins/main.html b/test/runtime/samples/deconflict-builtins/main.svelte
similarity index 100%
rename from test/runtime/samples/deconflict-builtins/main.html
rename to test/runtime/samples/deconflict-builtins/main.svelte
diff --git a/test/runtime/samples/deconflict-component-name-with-global/main.html b/test/runtime/samples/deconflict-component-name-with-global/main.svelte
similarity index 100%
rename from test/runtime/samples/deconflict-component-name-with-global/main.html
rename to test/runtime/samples/deconflict-component-name-with-global/main.svelte
diff --git a/test/runtime/samples/deconflict-component-name-with-module-global/main.html b/test/runtime/samples/deconflict-component-name-with-module-global/main.svelte
similarity index 100%
rename from test/runtime/samples/deconflict-component-name-with-module-global/main.html
rename to test/runtime/samples/deconflict-component-name-with-module-global/main.svelte
diff --git a/test/runtime/samples/deconflict-component-refs/main.html b/test/runtime/samples/deconflict-component-refs/main.svelte
similarity index 100%
rename from test/runtime/samples/deconflict-component-refs/main.html
rename to test/runtime/samples/deconflict-component-refs/main.svelte
diff --git a/test/runtime/samples/deconflict-contexts/main.html b/test/runtime/samples/deconflict-contexts/main.svelte
similarity index 100%
rename from test/runtime/samples/deconflict-contexts/main.html
rename to test/runtime/samples/deconflict-contexts/main.svelte
diff --git a/test/runtime/samples/deconflict-elements-indexes/main.html b/test/runtime/samples/deconflict-elements-indexes/main.svelte
similarity index 100%
rename from test/runtime/samples/deconflict-elements-indexes/main.html
rename to test/runtime/samples/deconflict-elements-indexes/main.svelte
diff --git a/test/runtime/samples/deconflict-non-helpers/main.html b/test/runtime/samples/deconflict-non-helpers/main.svelte
similarity index 100%
rename from test/runtime/samples/deconflict-non-helpers/main.html
rename to test/runtime/samples/deconflict-non-helpers/main.svelte
diff --git a/test/runtime/samples/deconflict-self/main.html b/test/runtime/samples/deconflict-self/main.html
deleted file mode 100644
index 30f524eb69..0000000000
--- a/test/runtime/samples/deconflict-self/main.html
+++ /dev/null
@@ -1,5 +0,0 @@
-<script>
-	import Main from './nested/main.html';
-</script>
-
-<Main/>
\ No newline at end of file
diff --git a/test/runtime/samples/deconflict-self/main.svelte b/test/runtime/samples/deconflict-self/main.svelte
new file mode 100644
index 0000000000..7010a66c88
--- /dev/null
+++ b/test/runtime/samples/deconflict-self/main.svelte
@@ -0,0 +1,5 @@
+<script>
+	import Main from './nested/main.svelte';
+</script>
+
+<Main/>
\ No newline at end of file
diff --git a/test/runtime/samples/deconflict-self/nested/main.html b/test/runtime/samples/deconflict-self/nested/main.svelte
similarity index 100%
rename from test/runtime/samples/deconflict-self/nested/main.html
rename to test/runtime/samples/deconflict-self/nested/main.svelte
diff --git a/test/runtime/samples/deconflict-template-1/main.html b/test/runtime/samples/deconflict-template-1/main.svelte
similarity index 100%
rename from test/runtime/samples/deconflict-template-1/main.html
rename to test/runtime/samples/deconflict-template-1/main.svelte
diff --git a/test/runtime/samples/deconflict-template-2/main.html b/test/runtime/samples/deconflict-template-2/main.svelte
similarity index 100%
rename from test/runtime/samples/deconflict-template-2/main.html
rename to test/runtime/samples/deconflict-template-2/main.svelte
diff --git a/test/runtime/samples/deconflict-vars/main.html b/test/runtime/samples/deconflict-vars/main.svelte
similarity index 100%
rename from test/runtime/samples/deconflict-vars/main.html
rename to test/runtime/samples/deconflict-vars/main.svelte
diff --git a/test/runtime/samples/default-data-function/main.html b/test/runtime/samples/default-data-function/main.svelte
similarity index 100%
rename from test/runtime/samples/default-data-function/main.html
rename to test/runtime/samples/default-data-function/main.svelte
diff --git a/test/runtime/samples/default-data-override/main.html b/test/runtime/samples/default-data-override/main.svelte
similarity index 100%
rename from test/runtime/samples/default-data-override/main.html
rename to test/runtime/samples/default-data-override/main.svelte
diff --git a/test/runtime/samples/default-data/main.html b/test/runtime/samples/default-data/main.svelte
similarity index 100%
rename from test/runtime/samples/default-data/main.html
rename to test/runtime/samples/default-data/main.svelte
diff --git a/test/runtime/samples/destroy-twice/main.html b/test/runtime/samples/destroy-twice/main.svelte
similarity index 100%
rename from test/runtime/samples/destroy-twice/main.html
rename to test/runtime/samples/destroy-twice/main.svelte
diff --git a/test/runtime/samples/destructuring/main.html b/test/runtime/samples/destructuring/main.svelte
similarity index 100%
rename from test/runtime/samples/destructuring/main.html
rename to test/runtime/samples/destructuring/main.svelte
diff --git a/test/runtime/samples/dev-warning-destroy-twice/main.html b/test/runtime/samples/dev-warning-destroy-twice/main.svelte
similarity index 100%
rename from test/runtime/samples/dev-warning-destroy-twice/main.html
rename to test/runtime/samples/dev-warning-destroy-twice/main.svelte
diff --git a/test/runtime/samples/dev-warning-helper/main.html b/test/runtime/samples/dev-warning-helper/main.svelte
similarity index 100%
rename from test/runtime/samples/dev-warning-helper/main.html
rename to test/runtime/samples/dev-warning-helper/main.svelte
diff --git a/test/runtime/samples/dev-warning-missing-data-binding/main.html b/test/runtime/samples/dev-warning-missing-data-binding/main.svelte
similarity index 100%
rename from test/runtime/samples/dev-warning-missing-data-binding/main.html
rename to test/runtime/samples/dev-warning-missing-data-binding/main.svelte
diff --git a/test/runtime/samples/dev-warning-missing-data-component/Foo.html b/test/runtime/samples/dev-warning-missing-data-component/Foo.svelte
similarity index 100%
rename from test/runtime/samples/dev-warning-missing-data-component/Foo.html
rename to test/runtime/samples/dev-warning-missing-data-component/Foo.svelte
diff --git a/test/runtime/samples/dev-warning-missing-data-component/main.html b/test/runtime/samples/dev-warning-missing-data-component/main.html
deleted file mode 100644
index 2bda6e2937..0000000000
--- a/test/runtime/samples/dev-warning-missing-data-component/main.html
+++ /dev/null
@@ -1,5 +0,0 @@
-<script>
-	import Foo from './Foo.html';
-</script>
-
-<Foo x={undefined}/>
\ No newline at end of file
diff --git a/test/runtime/samples/dev-warning-missing-data-component/main.svelte b/test/runtime/samples/dev-warning-missing-data-component/main.svelte
new file mode 100644
index 0000000000..15a5895b3d
--- /dev/null
+++ b/test/runtime/samples/dev-warning-missing-data-component/main.svelte
@@ -0,0 +1,5 @@
+<script>
+	import Foo from './Foo.svelte';
+</script>
+
+<Foo x={undefined}/>
\ No newline at end of file
diff --git a/test/runtime/samples/dev-warning-missing-data-each/main.html b/test/runtime/samples/dev-warning-missing-data-each/main.svelte
similarity index 100%
rename from test/runtime/samples/dev-warning-missing-data-each/main.html
rename to test/runtime/samples/dev-warning-missing-data-each/main.svelte
diff --git a/test/runtime/samples/dev-warning-missing-data-excludes-event/main.html b/test/runtime/samples/dev-warning-missing-data-excludes-event/main.svelte
similarity index 100%
rename from test/runtime/samples/dev-warning-missing-data-excludes-event/main.html
rename to test/runtime/samples/dev-warning-missing-data-excludes-event/main.svelte
diff --git a/test/runtime/samples/dev-warning-missing-data/main.html b/test/runtime/samples/dev-warning-missing-data/main.svelte
similarity index 100%
rename from test/runtime/samples/dev-warning-missing-data/main.html
rename to test/runtime/samples/dev-warning-missing-data/main.svelte
diff --git a/test/runtime/samples/dev-warning-readonly-computed/main.html b/test/runtime/samples/dev-warning-readonly-computed/main.svelte
similarity index 100%
rename from test/runtime/samples/dev-warning-readonly-computed/main.html
rename to test/runtime/samples/dev-warning-readonly-computed/main.svelte
diff --git a/test/runtime/samples/dev-warning-readonly-window-binding/main.html b/test/runtime/samples/dev-warning-readonly-window-binding/main.svelte
similarity index 100%
rename from test/runtime/samples/dev-warning-readonly-window-binding/main.html
rename to test/runtime/samples/dev-warning-readonly-window-binding/main.svelte
diff --git a/test/runtime/samples/document-event/main.html b/test/runtime/samples/document-event/main.svelte
similarity index 100%
rename from test/runtime/samples/document-event/main.html
rename to test/runtime/samples/document-event/main.svelte
diff --git a/test/runtime/samples/dynamic-component-bindings-recreated-b/Green.html b/test/runtime/samples/dynamic-component-bindings-recreated-b/Green.svelte
similarity index 100%
rename from test/runtime/samples/dynamic-component-bindings-recreated-b/Green.html
rename to test/runtime/samples/dynamic-component-bindings-recreated-b/Green.svelte
diff --git a/test/runtime/samples/dynamic-component-bindings-recreated-b/Red.html b/test/runtime/samples/dynamic-component-bindings-recreated-b/Red.svelte
similarity index 100%
rename from test/runtime/samples/dynamic-component-bindings-recreated-b/Red.html
rename to test/runtime/samples/dynamic-component-bindings-recreated-b/Red.svelte
diff --git a/test/runtime/samples/dynamic-component-bindings-recreated-b/main.html b/test/runtime/samples/dynamic-component-bindings-recreated-b/main.html
deleted file mode 100644
index cdae60e835..0000000000
--- a/test/runtime/samples/dynamic-component-bindings-recreated-b/main.html
+++ /dev/null
@@ -1,10 +0,0 @@
-<script>
-	import Green from './Green.html';
-	import Red from './Red.html';
-
-	export let foo;
-	export let x;
-</script>
-
-<p>parent {foo}</p>
-<svelte:component this="{x ? Green : Red}" bind:foo />
\ No newline at end of file
diff --git a/test/runtime/samples/dynamic-component-bindings-recreated-b/main.svelte b/test/runtime/samples/dynamic-component-bindings-recreated-b/main.svelte
new file mode 100644
index 0000000000..019718e5cb
--- /dev/null
+++ b/test/runtime/samples/dynamic-component-bindings-recreated-b/main.svelte
@@ -0,0 +1,10 @@
+<script>
+	import Green from './Green.svelte';
+	import Red from './Red.svelte';
+
+	export let foo;
+	export let x;
+</script>
+
+<p>parent {foo}</p>
+<svelte:component this="{x ? Green : Red}" bind:foo />
\ No newline at end of file
diff --git a/test/runtime/samples/dynamic-component-bindings-recreated/Green.html b/test/runtime/samples/dynamic-component-bindings-recreated/Green.svelte
similarity index 100%
rename from test/runtime/samples/dynamic-component-bindings-recreated/Green.html
rename to test/runtime/samples/dynamic-component-bindings-recreated/Green.svelte
diff --git a/test/runtime/samples/dynamic-component-bindings-recreated/Red.html b/test/runtime/samples/dynamic-component-bindings-recreated/Red.svelte
similarity index 100%
rename from test/runtime/samples/dynamic-component-bindings-recreated/Red.html
rename to test/runtime/samples/dynamic-component-bindings-recreated/Red.svelte
diff --git a/test/runtime/samples/dynamic-component-bindings-recreated/main.html b/test/runtime/samples/dynamic-component-bindings-recreated/main.html
deleted file mode 100644
index c91906e5df..0000000000
--- a/test/runtime/samples/dynamic-component-bindings-recreated/main.html
+++ /dev/null
@@ -1,9 +0,0 @@
-<script>
-	import Green from './Green.html';
-	import Red from './Red.html';
-
-	export let x;
-	export let foo;
-</script>
-
-<svelte:component this="{x ? Green : Red}" bind:foo />
\ No newline at end of file
diff --git a/test/runtime/samples/dynamic-component-bindings-recreated/main.svelte b/test/runtime/samples/dynamic-component-bindings-recreated/main.svelte
new file mode 100644
index 0000000000..011ac923b2
--- /dev/null
+++ b/test/runtime/samples/dynamic-component-bindings-recreated/main.svelte
@@ -0,0 +1,9 @@
+<script>
+	import Green from './Green.svelte';
+	import Red from './Red.svelte';
+
+	export let x;
+	export let foo;
+</script>
+
+<svelte:component this="{x ? Green : Red}" bind:foo />
\ No newline at end of file
diff --git a/test/runtime/samples/dynamic-component-bindings/Bar.html b/test/runtime/samples/dynamic-component-bindings/Bar.svelte
similarity index 100%
rename from test/runtime/samples/dynamic-component-bindings/Bar.html
rename to test/runtime/samples/dynamic-component-bindings/Bar.svelte
diff --git a/test/runtime/samples/dynamic-component-bindings/Foo.html b/test/runtime/samples/dynamic-component-bindings/Foo.svelte
similarity index 100%
rename from test/runtime/samples/dynamic-component-bindings/Foo.html
rename to test/runtime/samples/dynamic-component-bindings/Foo.svelte
diff --git a/test/runtime/samples/dynamic-component-bindings/main.html b/test/runtime/samples/dynamic-component-bindings/main.html
deleted file mode 100644
index 0df350a9f2..0000000000
--- a/test/runtime/samples/dynamic-component-bindings/main.html
+++ /dev/null
@@ -1,10 +0,0 @@
-<script>
-	import Foo from './Foo.html';
-	import Bar from './Bar.html';
-
-	export let x;
-	export let y;
-	export let z;
-</script>
-
-<svelte:component this="{ x ? Foo : Bar }" bind:y bind:z/>
\ No newline at end of file
diff --git a/test/runtime/samples/dynamic-component-bindings/main.svelte b/test/runtime/samples/dynamic-component-bindings/main.svelte
new file mode 100644
index 0000000000..31d0f86e5e
--- /dev/null
+++ b/test/runtime/samples/dynamic-component-bindings/main.svelte
@@ -0,0 +1,10 @@
+<script>
+	import Foo from './Foo.svelte';
+	import Bar from './Bar.svelte';
+
+	export let x;
+	export let y;
+	export let z;
+</script>
+
+<svelte:component this="{ x ? Foo : Bar }" bind:y bind:z/>
\ No newline at end of file
diff --git a/test/runtime/samples/dynamic-component-destroy-null/main.html b/test/runtime/samples/dynamic-component-destroy-null/main.svelte
similarity index 100%
rename from test/runtime/samples/dynamic-component-destroy-null/main.html
rename to test/runtime/samples/dynamic-component-destroy-null/main.svelte
diff --git a/test/runtime/samples/dynamic-component-events/Bar.html b/test/runtime/samples/dynamic-component-events/Bar.svelte
similarity index 100%
rename from test/runtime/samples/dynamic-component-events/Bar.html
rename to test/runtime/samples/dynamic-component-events/Bar.svelte
diff --git a/test/runtime/samples/dynamic-component-events/Foo.html b/test/runtime/samples/dynamic-component-events/Foo.svelte
similarity index 100%
rename from test/runtime/samples/dynamic-component-events/Foo.html
rename to test/runtime/samples/dynamic-component-events/Foo.svelte
diff --git a/test/runtime/samples/dynamic-component-events/main.html b/test/runtime/samples/dynamic-component-events/main.svelte
similarity index 58%
rename from test/runtime/samples/dynamic-component-events/main.html
rename to test/runtime/samples/dynamic-component-events/main.svelte
index 77856e8e63..f60e578289 100644
--- a/test/runtime/samples/dynamic-component-events/main.html
+++ b/test/runtime/samples/dynamic-component-events/main.svelte
@@ -1,6 +1,6 @@
 <script>
-	import Foo from './Foo.html';
-	import Bar from './Bar.html';
+	import Foo from './Foo.svelte';
+	import Bar from './Bar.svelte';
 
 	export let x;
 	export let selected;
diff --git a/test/runtime/samples/dynamic-component-in-if/Bar.html b/test/runtime/samples/dynamic-component-in-if/Bar.svelte
similarity index 100%
rename from test/runtime/samples/dynamic-component-in-if/Bar.html
rename to test/runtime/samples/dynamic-component-in-if/Bar.svelte
diff --git a/test/runtime/samples/dynamic-component-in-if/Foo.html b/test/runtime/samples/dynamic-component-in-if/Foo.svelte
similarity index 100%
rename from test/runtime/samples/dynamic-component-in-if/Foo.html
rename to test/runtime/samples/dynamic-component-in-if/Foo.svelte
diff --git a/test/runtime/samples/dynamic-component-in-if/main.html b/test/runtime/samples/dynamic-component-in-if/main.svelte
similarity index 57%
rename from test/runtime/samples/dynamic-component-in-if/main.html
rename to test/runtime/samples/dynamic-component-in-if/main.svelte
index dfd6f6a085..821dadf106 100644
--- a/test/runtime/samples/dynamic-component-in-if/main.html
+++ b/test/runtime/samples/dynamic-component-in-if/main.svelte
@@ -1,6 +1,6 @@
 <script>
-	import Foo from './Foo.html';
-	import Bar from './Bar.html';
+	import Foo from './Foo.svelte';
+	import Bar from './Bar.svelte';
 
 	export { Bar };
 	export let x = Foo;
diff --git a/test/runtime/samples/dynamic-component-inside-element/Bar.html b/test/runtime/samples/dynamic-component-inside-element/Bar.svelte
similarity index 100%
rename from test/runtime/samples/dynamic-component-inside-element/Bar.html
rename to test/runtime/samples/dynamic-component-inside-element/Bar.svelte
diff --git a/test/runtime/samples/dynamic-component-inside-element/Foo.html b/test/runtime/samples/dynamic-component-inside-element/Foo.svelte
similarity index 100%
rename from test/runtime/samples/dynamic-component-inside-element/Foo.html
rename to test/runtime/samples/dynamic-component-inside-element/Foo.svelte
diff --git a/test/runtime/samples/dynamic-component-inside-element/main.html b/test/runtime/samples/dynamic-component-inside-element/main.svelte
similarity index 57%
rename from test/runtime/samples/dynamic-component-inside-element/main.html
rename to test/runtime/samples/dynamic-component-inside-element/main.svelte
index 2a882c945f..e6efa606a4 100644
--- a/test/runtime/samples/dynamic-component-inside-element/main.html
+++ b/test/runtime/samples/dynamic-component-inside-element/main.svelte
@@ -1,6 +1,6 @@
 <script>
-	import Foo from './Foo.html';
-	import Bar from './Bar.html';
+	import Foo from './Foo.svelte';
+	import Bar from './Bar.svelte';
 
 	export let x;
 </script>
diff --git a/test/runtime/samples/dynamic-component-nulled-out/Foo.html b/test/runtime/samples/dynamic-component-nulled-out/Foo.svelte
similarity index 100%
rename from test/runtime/samples/dynamic-component-nulled-out/Foo.html
rename to test/runtime/samples/dynamic-component-nulled-out/Foo.svelte
diff --git a/test/runtime/samples/dynamic-component-nulled-out/main.html b/test/runtime/samples/dynamic-component-nulled-out/main.html
deleted file mode 100644
index b98ecb8f7e..0000000000
--- a/test/runtime/samples/dynamic-component-nulled-out/main.html
+++ /dev/null
@@ -1,7 +0,0 @@
-<script>
-	import Foo from './Foo.html';
-
-	export let Bar = Foo;
-</script>
-
-<svelte:component this={Bar}/>
\ No newline at end of file
diff --git a/test/runtime/samples/dynamic-component-nulled-out/main.svelte b/test/runtime/samples/dynamic-component-nulled-out/main.svelte
new file mode 100644
index 0000000000..2df6837267
--- /dev/null
+++ b/test/runtime/samples/dynamic-component-nulled-out/main.svelte
@@ -0,0 +1,7 @@
+<script>
+	import Foo from './Foo.svelte';
+
+	export let Bar = Foo;
+</script>
+
+<svelte:component this={Bar}/>
\ No newline at end of file
diff --git a/test/runtime/samples/dynamic-component-ref/Foo.html b/test/runtime/samples/dynamic-component-ref/Foo.svelte
similarity index 100%
rename from test/runtime/samples/dynamic-component-ref/Foo.html
rename to test/runtime/samples/dynamic-component-ref/Foo.svelte
diff --git a/test/runtime/samples/dynamic-component-ref/main.html b/test/runtime/samples/dynamic-component-ref/main.svelte
similarity index 72%
rename from test/runtime/samples/dynamic-component-ref/main.html
rename to test/runtime/samples/dynamic-component-ref/main.svelte
index fe9c52cab6..984f34fc7b 100644
--- a/test/runtime/samples/dynamic-component-ref/main.html
+++ b/test/runtime/samples/dynamic-component-ref/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Foo from './Foo.html';
+	import Foo from './Foo.svelte';
 
 	export let test;
 </script>
diff --git a/test/runtime/samples/dynamic-component-slot/Bar.html b/test/runtime/samples/dynamic-component-slot/Bar.svelte
similarity index 100%
rename from test/runtime/samples/dynamic-component-slot/Bar.html
rename to test/runtime/samples/dynamic-component-slot/Bar.svelte
diff --git a/test/runtime/samples/dynamic-component-slot/Baz.html b/test/runtime/samples/dynamic-component-slot/Baz.svelte
similarity index 100%
rename from test/runtime/samples/dynamic-component-slot/Baz.html
rename to test/runtime/samples/dynamic-component-slot/Baz.svelte
diff --git a/test/runtime/samples/dynamic-component-slot/Foo.html b/test/runtime/samples/dynamic-component-slot/Foo.svelte
similarity index 100%
rename from test/runtime/samples/dynamic-component-slot/Foo.html
rename to test/runtime/samples/dynamic-component-slot/Foo.svelte
diff --git a/test/runtime/samples/dynamic-component-slot/main.html b/test/runtime/samples/dynamic-component-slot/main.svelte
similarity index 78%
rename from test/runtime/samples/dynamic-component-slot/main.html
rename to test/runtime/samples/dynamic-component-slot/main.svelte
index 32f1ecce19..99bcf9e64f 100644
--- a/test/runtime/samples/dynamic-component-slot/main.html
+++ b/test/runtime/samples/dynamic-component-slot/main.svelte
@@ -1,7 +1,7 @@
 <script>
-	import Foo from './Foo.html';
-	import Bar from './Bar.html';
-	import Baz from './Baz.html';
+	import Foo from './Foo.svelte';
+	import Bar from './Bar.svelte';
+	import Baz from './Baz.svelte';
 
 	export let x;
 	export let tag = 'you\'re it';
diff --git a/test/runtime/samples/dynamic-component-update-existing-instance/Bar.html b/test/runtime/samples/dynamic-component-update-existing-instance/Bar.svelte
similarity index 100%
rename from test/runtime/samples/dynamic-component-update-existing-instance/Bar.html
rename to test/runtime/samples/dynamic-component-update-existing-instance/Bar.svelte
diff --git a/test/runtime/samples/dynamic-component-update-existing-instance/Foo.html b/test/runtime/samples/dynamic-component-update-existing-instance/Foo.svelte
similarity index 100%
rename from test/runtime/samples/dynamic-component-update-existing-instance/Foo.html
rename to test/runtime/samples/dynamic-component-update-existing-instance/Foo.svelte
diff --git a/test/runtime/samples/dynamic-component-update-existing-instance/main.html b/test/runtime/samples/dynamic-component-update-existing-instance/main.html
deleted file mode 100644
index efa9394d30..0000000000
--- a/test/runtime/samples/dynamic-component-update-existing-instance/main.html
+++ /dev/null
@@ -1,8 +0,0 @@
-<script>
-	import Foo from './Foo.html';
-	import Bar from './Bar.html';
-
-	export let x;
-</script>
-
-<svelte:component this="{ x ? Foo : Bar }" x='{x}'/>
\ No newline at end of file
diff --git a/test/runtime/samples/dynamic-component-update-existing-instance/main.svelte b/test/runtime/samples/dynamic-component-update-existing-instance/main.svelte
new file mode 100644
index 0000000000..6e2a8cde5e
--- /dev/null
+++ b/test/runtime/samples/dynamic-component-update-existing-instance/main.svelte
@@ -0,0 +1,8 @@
+<script>
+	import Foo from './Foo.svelte';
+	import Bar from './Bar.svelte';
+
+	export let x;
+</script>
+
+<svelte:component this="{ x ? Foo : Bar }" x='{x}'/>
\ No newline at end of file
diff --git a/test/runtime/samples/dynamic-component/Bar.html b/test/runtime/samples/dynamic-component/Bar.svelte
similarity index 100%
rename from test/runtime/samples/dynamic-component/Bar.html
rename to test/runtime/samples/dynamic-component/Bar.svelte
diff --git a/test/runtime/samples/dynamic-component/Foo.html b/test/runtime/samples/dynamic-component/Foo.svelte
similarity index 100%
rename from test/runtime/samples/dynamic-component/Foo.html
rename to test/runtime/samples/dynamic-component/Foo.svelte
diff --git a/test/runtime/samples/dynamic-component/main.html b/test/runtime/samples/dynamic-component/main.html
deleted file mode 100644
index efa9394d30..0000000000
--- a/test/runtime/samples/dynamic-component/main.html
+++ /dev/null
@@ -1,8 +0,0 @@
-<script>
-	import Foo from './Foo.html';
-	import Bar from './Bar.html';
-
-	export let x;
-</script>
-
-<svelte:component this="{ x ? Foo : Bar }" x='{x}'/>
\ No newline at end of file
diff --git a/test/runtime/samples/dynamic-component/main.svelte b/test/runtime/samples/dynamic-component/main.svelte
new file mode 100644
index 0000000000..6e2a8cde5e
--- /dev/null
+++ b/test/runtime/samples/dynamic-component/main.svelte
@@ -0,0 +1,8 @@
+<script>
+	import Foo from './Foo.svelte';
+	import Bar from './Bar.svelte';
+
+	export let x;
+</script>
+
+<svelte:component this="{ x ? Foo : Bar }" x='{x}'/>
\ No newline at end of file
diff --git a/test/runtime/samples/each-block-array-literal/main.html b/test/runtime/samples/each-block-array-literal/main.svelte
similarity index 100%
rename from test/runtime/samples/each-block-array-literal/main.html
rename to test/runtime/samples/each-block-array-literal/main.svelte
diff --git a/test/runtime/samples/each-block-containing-component-in-if/Nested.html b/test/runtime/samples/each-block-containing-component-in-if/Nested.svelte
similarity index 100%
rename from test/runtime/samples/each-block-containing-component-in-if/Nested.html
rename to test/runtime/samples/each-block-containing-component-in-if/Nested.svelte
diff --git a/test/runtime/samples/each-block-containing-component-in-if/main.html b/test/runtime/samples/each-block-containing-component-in-if/main.svelte
similarity index 67%
rename from test/runtime/samples/each-block-containing-component-in-if/main.html
rename to test/runtime/samples/each-block-containing-component-in-if/main.svelte
index 16f042a277..049948fa56 100644
--- a/test/runtime/samples/each-block-containing-component-in-if/main.html
+++ b/test/runtime/samples/each-block-containing-component-in-if/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Nested from './Nested.html';
+	import Nested from './Nested.svelte';
 
 	export let show;
 	export let fields;
diff --git a/test/runtime/samples/each-block-containing-if/main.html b/test/runtime/samples/each-block-containing-if/main.svelte
similarity index 100%
rename from test/runtime/samples/each-block-containing-if/main.html
rename to test/runtime/samples/each-block-containing-if/main.svelte
diff --git a/test/runtime/samples/each-block-deconflict-name-context/main.html b/test/runtime/samples/each-block-deconflict-name-context/main.svelte
similarity index 100%
rename from test/runtime/samples/each-block-deconflict-name-context/main.html
rename to test/runtime/samples/each-block-deconflict-name-context/main.svelte
diff --git a/test/runtime/samples/each-block-destructured-array-sparse/main.html b/test/runtime/samples/each-block-destructured-array-sparse/main.svelte
similarity index 100%
rename from test/runtime/samples/each-block-destructured-array-sparse/main.html
rename to test/runtime/samples/each-block-destructured-array-sparse/main.svelte
diff --git a/test/runtime/samples/each-block-destructured-array/main.html b/test/runtime/samples/each-block-destructured-array/main.svelte
similarity index 100%
rename from test/runtime/samples/each-block-destructured-array/main.html
rename to test/runtime/samples/each-block-destructured-array/main.svelte
diff --git a/test/runtime/samples/each-block-destructured-object-binding/main.html b/test/runtime/samples/each-block-destructured-object-binding/main.svelte
similarity index 100%
rename from test/runtime/samples/each-block-destructured-object-binding/main.html
rename to test/runtime/samples/each-block-destructured-object-binding/main.svelte
diff --git a/test/runtime/samples/each-block-destructured-object/main.html b/test/runtime/samples/each-block-destructured-object/main.svelte
similarity index 100%
rename from test/runtime/samples/each-block-destructured-object/main.html
rename to test/runtime/samples/each-block-destructured-object/main.svelte
diff --git a/test/runtime/samples/each-block-dynamic-else-static/main.html b/test/runtime/samples/each-block-dynamic-else-static/main.svelte
similarity index 100%
rename from test/runtime/samples/each-block-dynamic-else-static/main.html
rename to test/runtime/samples/each-block-dynamic-else-static/main.svelte
diff --git a/test/runtime/samples/each-block-else-mount-or-intro/Widget.html b/test/runtime/samples/each-block-else-mount-or-intro/Widget.svelte
similarity index 100%
rename from test/runtime/samples/each-block-else-mount-or-intro/Widget.html
rename to test/runtime/samples/each-block-else-mount-or-intro/Widget.svelte
diff --git a/test/runtime/samples/each-block-else-mount-or-intro/main.html b/test/runtime/samples/each-block-else-mount-or-intro/main.svelte
similarity index 73%
rename from test/runtime/samples/each-block-else-mount-or-intro/main.html
rename to test/runtime/samples/each-block-else-mount-or-intro/main.svelte
index 949eb9b096..5b4d2e37a6 100644
--- a/test/runtime/samples/each-block-else-mount-or-intro/main.html
+++ b/test/runtime/samples/each-block-else-mount-or-intro/main.svelte
@@ -1,7 +1,7 @@
 <script>
 	export let items;
 
-	import Widget from './Widget.html';
+	import Widget from './Widget.svelte';
 </script>
 
 {#each items as item}
diff --git a/test/runtime/samples/each-block-else-starts-empty/main.html b/test/runtime/samples/each-block-else-starts-empty/main.svelte
similarity index 100%
rename from test/runtime/samples/each-block-else-starts-empty/main.html
rename to test/runtime/samples/each-block-else-starts-empty/main.svelte
diff --git a/test/runtime/samples/each-block-else/main.html b/test/runtime/samples/each-block-else/main.svelte
similarity index 100%
rename from test/runtime/samples/each-block-else/main.html
rename to test/runtime/samples/each-block-else/main.svelte
diff --git a/test/runtime/samples/each-block-empty-outro/Thing.html b/test/runtime/samples/each-block-empty-outro/Thing.svelte
similarity index 100%
rename from test/runtime/samples/each-block-empty-outro/Thing.html
rename to test/runtime/samples/each-block-empty-outro/Thing.svelte
diff --git a/test/runtime/samples/each-block-empty-outro/main.html b/test/runtime/samples/each-block-empty-outro/main.svelte
similarity index 79%
rename from test/runtime/samples/each-block-empty-outro/main.html
rename to test/runtime/samples/each-block-empty-outro/main.svelte
index 325cbbcf45..338f471d31 100644
--- a/test/runtime/samples/each-block-empty-outro/main.html
+++ b/test/runtime/samples/each-block-empty-outro/main.svelte
@@ -2,7 +2,7 @@
 	export let visible;
 	export let empty;
 
-	import Thing from './Thing.html';
+	import Thing from './Thing.svelte';
 </script>
 
 {#if visible}
diff --git a/test/runtime/samples/each-block-function/main.html b/test/runtime/samples/each-block-function/main.svelte
similarity index 100%
rename from test/runtime/samples/each-block-function/main.html
rename to test/runtime/samples/each-block-function/main.svelte
diff --git a/test/runtime/samples/each-block-in-if-block/main.html b/test/runtime/samples/each-block-in-if-block/main.svelte
similarity index 100%
rename from test/runtime/samples/each-block-in-if-block/main.html
rename to test/runtime/samples/each-block-in-if-block/main.svelte
diff --git a/test/runtime/samples/each-block-index-only/main.html b/test/runtime/samples/each-block-index-only/main.svelte
similarity index 100%
rename from test/runtime/samples/each-block-index-only/main.html
rename to test/runtime/samples/each-block-index-only/main.svelte
diff --git a/test/runtime/samples/each-block-indexed/main.html b/test/runtime/samples/each-block-indexed/main.svelte
similarity index 100%
rename from test/runtime/samples/each-block-indexed/main.html
rename to test/runtime/samples/each-block-indexed/main.svelte
diff --git a/test/runtime/samples/each-block-keyed-dynamic/main.html b/test/runtime/samples/each-block-keyed-dynamic/main.svelte
similarity index 100%
rename from test/runtime/samples/each-block-keyed-dynamic/main.html
rename to test/runtime/samples/each-block-keyed-dynamic/main.svelte
diff --git a/test/runtime/samples/each-block-keyed-empty/main.html b/test/runtime/samples/each-block-keyed-empty/main.svelte
similarity index 100%
rename from test/runtime/samples/each-block-keyed-empty/main.html
rename to test/runtime/samples/each-block-keyed-empty/main.svelte
diff --git a/test/runtime/samples/each-block-keyed-non-prop/main.html b/test/runtime/samples/each-block-keyed-non-prop/main.svelte
similarity index 100%
rename from test/runtime/samples/each-block-keyed-non-prop/main.html
rename to test/runtime/samples/each-block-keyed-non-prop/main.svelte
diff --git a/test/runtime/samples/each-block-keyed-random-permute/main.html b/test/runtime/samples/each-block-keyed-random-permute/main.svelte
similarity index 100%
rename from test/runtime/samples/each-block-keyed-random-permute/main.html
rename to test/runtime/samples/each-block-keyed-random-permute/main.svelte
diff --git a/test/runtime/samples/each-block-keyed-siblings/main.html b/test/runtime/samples/each-block-keyed-siblings/main.svelte
similarity index 100%
rename from test/runtime/samples/each-block-keyed-siblings/main.html
rename to test/runtime/samples/each-block-keyed-siblings/main.svelte
diff --git a/test/runtime/samples/each-block-keyed-static/main.html b/test/runtime/samples/each-block-keyed-static/main.svelte
similarity index 100%
rename from test/runtime/samples/each-block-keyed-static/main.html
rename to test/runtime/samples/each-block-keyed-static/main.svelte
diff --git a/test/runtime/samples/each-block-keyed-unshift/Nested.html b/test/runtime/samples/each-block-keyed-unshift/Nested.svelte
similarity index 100%
rename from test/runtime/samples/each-block-keyed-unshift/Nested.html
rename to test/runtime/samples/each-block-keyed-unshift/Nested.svelte
diff --git a/test/runtime/samples/each-block-keyed-unshift/main.html b/test/runtime/samples/each-block-keyed-unshift/main.svelte
similarity index 70%
rename from test/runtime/samples/each-block-keyed-unshift/main.html
rename to test/runtime/samples/each-block-keyed-unshift/main.svelte
index 5af62d4e08..b8954e17fd 100644
--- a/test/runtime/samples/each-block-keyed-unshift/main.html
+++ b/test/runtime/samples/each-block-keyed-unshift/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Nested from './Nested.html';
+	import Nested from './Nested.svelte';
 
 	export let titles;
 </script>
diff --git a/test/runtime/samples/each-block-keyed/main.html b/test/runtime/samples/each-block-keyed/main.svelte
similarity index 100%
rename from test/runtime/samples/each-block-keyed/main.html
rename to test/runtime/samples/each-block-keyed/main.svelte
diff --git a/test/runtime/samples/each-block-random-permute/main.html b/test/runtime/samples/each-block-random-permute/main.svelte
similarity index 100%
rename from test/runtime/samples/each-block-random-permute/main.html
rename to test/runtime/samples/each-block-random-permute/main.svelte
diff --git a/test/runtime/samples/each-block-scope-shadow/main.html b/test/runtime/samples/each-block-scope-shadow/main.svelte
similarity index 100%
rename from test/runtime/samples/each-block-scope-shadow/main.html
rename to test/runtime/samples/each-block-scope-shadow/main.svelte
diff --git a/test/runtime/samples/each-block-static/main.html b/test/runtime/samples/each-block-static/main.svelte
similarity index 100%
rename from test/runtime/samples/each-block-static/main.html
rename to test/runtime/samples/each-block-static/main.svelte
diff --git a/test/runtime/samples/each-block-text-node/main.html b/test/runtime/samples/each-block-text-node/main.svelte
similarity index 100%
rename from test/runtime/samples/each-block-text-node/main.html
rename to test/runtime/samples/each-block-text-node/main.svelte
diff --git a/test/runtime/samples/each-block/main.html b/test/runtime/samples/each-block/main.svelte
similarity index 100%
rename from test/runtime/samples/each-block/main.html
rename to test/runtime/samples/each-block/main.svelte
diff --git a/test/runtime/samples/each-blocks-expression/main.html b/test/runtime/samples/each-blocks-expression/main.svelte
similarity index 100%
rename from test/runtime/samples/each-blocks-expression/main.html
rename to test/runtime/samples/each-blocks-expression/main.svelte
diff --git a/test/runtime/samples/each-blocks-nested-b/main.html b/test/runtime/samples/each-blocks-nested-b/main.svelte
similarity index 100%
rename from test/runtime/samples/each-blocks-nested-b/main.html
rename to test/runtime/samples/each-blocks-nested-b/main.svelte
diff --git a/test/runtime/samples/each-blocks-nested/main.html b/test/runtime/samples/each-blocks-nested/main.svelte
similarity index 100%
rename from test/runtime/samples/each-blocks-nested/main.html
rename to test/runtime/samples/each-blocks-nested/main.svelte
diff --git a/test/runtime/samples/element-invalid-name/main.html b/test/runtime/samples/element-invalid-name/main.svelte
similarity index 100%
rename from test/runtime/samples/element-invalid-name/main.html
rename to test/runtime/samples/element-invalid-name/main.svelte
diff --git a/test/runtime/samples/element-source-location/Foo.html b/test/runtime/samples/element-source-location/Foo.svelte
similarity index 100%
rename from test/runtime/samples/element-source-location/Foo.html
rename to test/runtime/samples/element-source-location/Foo.svelte
diff --git a/test/runtime/samples/element-source-location/main.html b/test/runtime/samples/element-source-location/main.svelte
similarity index 54%
rename from test/runtime/samples/element-source-location/main.html
rename to test/runtime/samples/element-source-location/main.svelte
index ca70895728..38855ef3ac 100644
--- a/test/runtime/samples/element-source-location/main.html
+++ b/test/runtime/samples/element-source-location/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Foo from './Foo.html';
+	import Foo from './Foo.svelte';
 </script>
 
 <h1>this is a header</h1>
diff --git a/test/runtime/samples/empty-style-block/main.html b/test/runtime/samples/empty-style-block/main.svelte
similarity index 100%
rename from test/runtime/samples/empty-style-block/main.html
rename to test/runtime/samples/empty-style-block/main.svelte
diff --git a/test/runtime/samples/escape-template-literals/Widget.html b/test/runtime/samples/escape-template-literals/Widget.svelte
similarity index 100%
rename from test/runtime/samples/escape-template-literals/Widget.html
rename to test/runtime/samples/escape-template-literals/Widget.svelte
diff --git a/test/runtime/samples/escape-template-literals/main.html b/test/runtime/samples/escape-template-literals/main.svelte
similarity index 75%
rename from test/runtime/samples/escape-template-literals/main.html
rename to test/runtime/samples/escape-template-literals/main.svelte
index bfd016de6b..d26aa6ea63 100644
--- a/test/runtime/samples/escape-template-literals/main.html
+++ b/test/runtime/samples/escape-template-literals/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Widget from './Widget.html';
+	import Widget from './Widget.svelte';
 </script>
 
 <code>`$&#123;foo}\n`</code>
diff --git a/test/runtime/samples/escaped-text/main.html b/test/runtime/samples/escaped-text/main.svelte
similarity index 100%
rename from test/runtime/samples/escaped-text/main.html
rename to test/runtime/samples/escaped-text/main.svelte
diff --git a/test/runtime/samples/event-handler-console-log/main.html b/test/runtime/samples/event-handler-console-log/main.svelte
similarity index 100%
rename from test/runtime/samples/event-handler-console-log/main.html
rename to test/runtime/samples/event-handler-console-log/main.svelte
diff --git a/test/runtime/samples/event-handler-deconflicted/main.html b/test/runtime/samples/event-handler-deconflicted/main.svelte
similarity index 100%
rename from test/runtime/samples/event-handler-deconflicted/main.html
rename to test/runtime/samples/event-handler-deconflicted/main.svelte
diff --git a/test/runtime/samples/event-handler-each-context/main.html b/test/runtime/samples/event-handler-each-context/main.svelte
similarity index 100%
rename from test/runtime/samples/event-handler-each-context/main.html
rename to test/runtime/samples/event-handler-each-context/main.svelte
diff --git a/test/runtime/samples/event-handler-each-deconflicted/main.html b/test/runtime/samples/event-handler-each-deconflicted/main.svelte
similarity index 100%
rename from test/runtime/samples/event-handler-each-deconflicted/main.html
rename to test/runtime/samples/event-handler-each-deconflicted/main.svelte
diff --git a/test/runtime/samples/event-handler-each-this/main.html b/test/runtime/samples/event-handler-each-this/main.svelte
similarity index 100%
rename from test/runtime/samples/event-handler-each-this/main.html
rename to test/runtime/samples/event-handler-each-this/main.svelte
diff --git a/test/runtime/samples/event-handler-each/main.html b/test/runtime/samples/event-handler-each/main.svelte
similarity index 100%
rename from test/runtime/samples/event-handler-each/main.html
rename to test/runtime/samples/event-handler-each/main.svelte
diff --git a/test/runtime/samples/event-handler-event-methods/main.html b/test/runtime/samples/event-handler-event-methods/main.svelte
similarity index 100%
rename from test/runtime/samples/event-handler-event-methods/main.html
rename to test/runtime/samples/event-handler-event-methods/main.svelte
diff --git a/test/runtime/samples/event-handler-hoisted/main.html b/test/runtime/samples/event-handler-hoisted/main.svelte
similarity index 100%
rename from test/runtime/samples/event-handler-hoisted/main.html
rename to test/runtime/samples/event-handler-hoisted/main.svelte
diff --git a/test/runtime/samples/event-handler-modifier-once/main.html b/test/runtime/samples/event-handler-modifier-once/main.svelte
similarity index 100%
rename from test/runtime/samples/event-handler-modifier-once/main.html
rename to test/runtime/samples/event-handler-modifier-once/main.svelte
diff --git a/test/runtime/samples/event-handler-modifier-prevent-default/main.html b/test/runtime/samples/event-handler-modifier-prevent-default/main.svelte
similarity index 100%
rename from test/runtime/samples/event-handler-modifier-prevent-default/main.html
rename to test/runtime/samples/event-handler-modifier-prevent-default/main.svelte
diff --git a/test/runtime/samples/event-handler-modifier-stop-propagation/main.html b/test/runtime/samples/event-handler-modifier-stop-propagation/main.svelte
similarity index 100%
rename from test/runtime/samples/event-handler-modifier-stop-propagation/main.html
rename to test/runtime/samples/event-handler-modifier-stop-propagation/main.svelte
diff --git a/test/runtime/samples/event-handler-removal/main.html b/test/runtime/samples/event-handler-removal/main.svelte
similarity index 100%
rename from test/runtime/samples/event-handler-removal/main.html
rename to test/runtime/samples/event-handler-removal/main.svelte
diff --git a/test/runtime/samples/event-handler-sanitize/main.html b/test/runtime/samples/event-handler-sanitize/main.svelte
similarity index 100%
rename from test/runtime/samples/event-handler-sanitize/main.html
rename to test/runtime/samples/event-handler-sanitize/main.svelte
diff --git a/test/runtime/samples/event-handler-shorthand-component/Widget.html b/test/runtime/samples/event-handler-shorthand-component/Widget.svelte
similarity index 100%
rename from test/runtime/samples/event-handler-shorthand-component/Widget.html
rename to test/runtime/samples/event-handler-shorthand-component/Widget.svelte
diff --git a/test/runtime/samples/event-handler-shorthand-component/main.html b/test/runtime/samples/event-handler-shorthand-component/main.html
deleted file mode 100644
index 26586d3fd3..0000000000
--- a/test/runtime/samples/event-handler-shorthand-component/main.html
+++ /dev/null
@@ -1,5 +0,0 @@
-<script>
-	import Widget from './Widget.html';
-</script>
-
-<Widget on:foo/>
\ No newline at end of file
diff --git a/test/runtime/samples/event-handler-shorthand-component/main.svelte b/test/runtime/samples/event-handler-shorthand-component/main.svelte
new file mode 100644
index 0000000000..df21f9e8b8
--- /dev/null
+++ b/test/runtime/samples/event-handler-shorthand-component/main.svelte
@@ -0,0 +1,5 @@
+<script>
+	import Widget from './Widget.svelte';
+</script>
+
+<Widget on:foo/>
\ No newline at end of file
diff --git a/test/runtime/samples/event-handler-shorthand-dynamic-component/Widget.html b/test/runtime/samples/event-handler-shorthand-dynamic-component/Widget.svelte
similarity index 100%
rename from test/runtime/samples/event-handler-shorthand-dynamic-component/Widget.html
rename to test/runtime/samples/event-handler-shorthand-dynamic-component/Widget.svelte
diff --git a/test/runtime/samples/event-handler-shorthand-dynamic-component/main.html b/test/runtime/samples/event-handler-shorthand-dynamic-component/main.svelte
similarity index 61%
rename from test/runtime/samples/event-handler-shorthand-dynamic-component/main.html
rename to test/runtime/samples/event-handler-shorthand-dynamic-component/main.svelte
index f38a4d30bb..f6c5494ce4 100644
--- a/test/runtime/samples/event-handler-shorthand-dynamic-component/main.html
+++ b/test/runtime/samples/event-handler-shorthand-dynamic-component/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Widget from './Widget.html';
+	import Widget from './Widget.svelte';
 </script>
 
 <svelte:component this={Widget} on:foo/>
diff --git a/test/runtime/samples/event-handler-this-methods/main.html b/test/runtime/samples/event-handler-this-methods/main.svelte
similarity index 100%
rename from test/runtime/samples/event-handler-this-methods/main.html
rename to test/runtime/samples/event-handler-this-methods/main.svelte
diff --git a/test/runtime/samples/event-handler/main.html b/test/runtime/samples/event-handler/main.svelte
similarity index 100%
rename from test/runtime/samples/event-handler/main.html
rename to test/runtime/samples/event-handler/main.svelte
diff --git a/test/runtime/samples/flush-before-bindings/Nested.html b/test/runtime/samples/flush-before-bindings/Nested.svelte
similarity index 87%
rename from test/runtime/samples/flush-before-bindings/Nested.html
rename to test/runtime/samples/flush-before-bindings/Nested.svelte
index a632b585a8..0a1721d308 100644
--- a/test/runtime/samples/flush-before-bindings/Nested.html
+++ b/test/runtime/samples/flush-before-bindings/Nested.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Visibility from './Visibility.html';
+	import Visibility from './Visibility.svelte';
 	import counter from './counter.js';
 
 	export let things = ['first thing', 'second thing'];
diff --git a/test/runtime/samples/flush-before-bindings/Visibility.html b/test/runtime/samples/flush-before-bindings/Visibility.svelte
similarity index 100%
rename from test/runtime/samples/flush-before-bindings/Visibility.html
rename to test/runtime/samples/flush-before-bindings/Visibility.svelte
diff --git a/test/runtime/samples/flush-before-bindings/main.html b/test/runtime/samples/flush-before-bindings/main.svelte
similarity index 73%
rename from test/runtime/samples/flush-before-bindings/main.html
rename to test/runtime/samples/flush-before-bindings/main.svelte
index 74081c9511..326222c818 100644
--- a/test/runtime/samples/flush-before-bindings/main.html
+++ b/test/runtime/samples/flush-before-bindings/main.svelte
@@ -1,6 +1,6 @@
 <script>
 	import { beforeUpdate } from 'svelte';
-	import Nested from './Nested.html';
+	import Nested from './Nested.svelte';
 
 	export let snapshots;
 	export let visibleThings = [];
diff --git a/test/runtime/samples/function-in-expression/main.html b/test/runtime/samples/function-in-expression/main.svelte
similarity index 100%
rename from test/runtime/samples/function-in-expression/main.html
rename to test/runtime/samples/function-in-expression/main.svelte
diff --git a/test/runtime/samples/get-after-destroy/main.html b/test/runtime/samples/get-after-destroy/main.svelte
similarity index 100%
rename from test/runtime/samples/get-after-destroy/main.html
rename to test/runtime/samples/get-after-destroy/main.svelte
diff --git a/test/runtime/samples/globals-accessible-directly-process/main.html b/test/runtime/samples/globals-accessible-directly-process/main.svelte
similarity index 100%
rename from test/runtime/samples/globals-accessible-directly-process/main.html
rename to test/runtime/samples/globals-accessible-directly-process/main.svelte
diff --git a/test/runtime/samples/globals-accessible-directly/main.html b/test/runtime/samples/globals-accessible-directly/main.svelte
similarity index 100%
rename from test/runtime/samples/globals-accessible-directly/main.html
rename to test/runtime/samples/globals-accessible-directly/main.svelte
diff --git a/test/runtime/samples/globals-not-dereferenced/main.html b/test/runtime/samples/globals-not-dereferenced/main.svelte
similarity index 100%
rename from test/runtime/samples/globals-not-dereferenced/main.html
rename to test/runtime/samples/globals-not-dereferenced/main.svelte
diff --git a/test/runtime/samples/globals-not-overwritten-by-bindings/main.html b/test/runtime/samples/globals-not-overwritten-by-bindings/main.svelte
similarity index 100%
rename from test/runtime/samples/globals-not-overwritten-by-bindings/main.html
rename to test/runtime/samples/globals-not-overwritten-by-bindings/main.svelte
diff --git a/test/runtime/samples/globals-shadowed-by-data/main.html b/test/runtime/samples/globals-shadowed-by-data/main.svelte
similarity index 100%
rename from test/runtime/samples/globals-shadowed-by-data/main.html
rename to test/runtime/samples/globals-shadowed-by-data/main.svelte
diff --git a/test/runtime/samples/globals-shadowed-by-helpers/main.html b/test/runtime/samples/globals-shadowed-by-helpers/main.svelte
similarity index 100%
rename from test/runtime/samples/globals-shadowed-by-helpers/main.html
rename to test/runtime/samples/globals-shadowed-by-helpers/main.svelte
diff --git a/test/runtime/samples/hash-in-attribute/main.html b/test/runtime/samples/hash-in-attribute/main.svelte
similarity index 100%
rename from test/runtime/samples/hash-in-attribute/main.html
rename to test/runtime/samples/hash-in-attribute/main.svelte
diff --git a/test/runtime/samples/head-if-block/main.html b/test/runtime/samples/head-if-block/main.svelte
similarity index 100%
rename from test/runtime/samples/head-if-block/main.html
rename to test/runtime/samples/head-if-block/main.svelte
diff --git a/test/runtime/samples/head-title-dynamic-simple/main.html b/test/runtime/samples/head-title-dynamic-simple/main.svelte
similarity index 100%
rename from test/runtime/samples/head-title-dynamic-simple/main.html
rename to test/runtime/samples/head-title-dynamic-simple/main.svelte
diff --git a/test/runtime/samples/head-title-dynamic/main.html b/test/runtime/samples/head-title-dynamic/main.svelte
similarity index 100%
rename from test/runtime/samples/head-title-dynamic/main.html
rename to test/runtime/samples/head-title-dynamic/main.svelte
diff --git a/test/runtime/samples/head-title-static/main.html b/test/runtime/samples/head-title-static/main.svelte
similarity index 100%
rename from test/runtime/samples/head-title-static/main.html
rename to test/runtime/samples/head-title-static/main.svelte
diff --git a/test/runtime/samples/hello-world/main.html b/test/runtime/samples/hello-world/main.svelte
similarity index 100%
rename from test/runtime/samples/hello-world/main.html
rename to test/runtime/samples/hello-world/main.svelte
diff --git a/test/runtime/samples/helpers-not-call-expression/main.html b/test/runtime/samples/helpers-not-call-expression/main.svelte
similarity index 100%
rename from test/runtime/samples/helpers-not-call-expression/main.html
rename to test/runtime/samples/helpers-not-call-expression/main.svelte
diff --git a/test/runtime/samples/helpers/main.html b/test/runtime/samples/helpers/main.svelte
similarity index 100%
rename from test/runtime/samples/helpers/main.html
rename to test/runtime/samples/helpers/main.svelte
diff --git a/test/runtime/samples/html-entities-inside-elements/main.html b/test/runtime/samples/html-entities-inside-elements/main.svelte
similarity index 100%
rename from test/runtime/samples/html-entities-inside-elements/main.html
rename to test/runtime/samples/html-entities-inside-elements/main.svelte
diff --git a/test/runtime/samples/html-entities/main.html b/test/runtime/samples/html-entities/main.svelte
similarity index 100%
rename from test/runtime/samples/html-entities/main.html
rename to test/runtime/samples/html-entities/main.svelte
diff --git a/test/runtime/samples/html-non-entities-inside-elements/main.html b/test/runtime/samples/html-non-entities-inside-elements/main.svelte
similarity index 100%
rename from test/runtime/samples/html-non-entities-inside-elements/main.html
rename to test/runtime/samples/html-non-entities-inside-elements/main.svelte
diff --git a/test/runtime/samples/if-block-component-without-outro/Widget.html b/test/runtime/samples/if-block-component-without-outro/Widget.svelte
similarity index 100%
rename from test/runtime/samples/if-block-component-without-outro/Widget.html
rename to test/runtime/samples/if-block-component-without-outro/Widget.svelte
diff --git a/test/runtime/samples/if-block-component-without-outro/main.html b/test/runtime/samples/if-block-component-without-outro/main.svelte
similarity index 57%
rename from test/runtime/samples/if-block-component-without-outro/main.html
rename to test/runtime/samples/if-block-component-without-outro/main.svelte
index 45498b97a1..2efb43b030 100644
--- a/test/runtime/samples/if-block-component-without-outro/main.html
+++ b/test/runtime/samples/if-block-component-without-outro/main.svelte
@@ -1,7 +1,7 @@
 <script>
 	export let foo;
 
-	import Widget from './Widget.html';
+	import Widget from './Widget.svelte';
 </script>
 
 {#if foo}
diff --git a/test/runtime/samples/if-block-else-in-each/main.html b/test/runtime/samples/if-block-else-in-each/main.svelte
similarity index 100%
rename from test/runtime/samples/if-block-else-in-each/main.html
rename to test/runtime/samples/if-block-else-in-each/main.svelte
diff --git a/test/runtime/samples/if-block-else-partial-outro/Foo.html b/test/runtime/samples/if-block-else-partial-outro/Foo.svelte
similarity index 100%
rename from test/runtime/samples/if-block-else-partial-outro/Foo.html
rename to test/runtime/samples/if-block-else-partial-outro/Foo.svelte
diff --git a/test/runtime/samples/if-block-else-partial-outro/main.html b/test/runtime/samples/if-block-else-partial-outro/main.svelte
similarity index 73%
rename from test/runtime/samples/if-block-else-partial-outro/main.html
rename to test/runtime/samples/if-block-else-partial-outro/main.svelte
index 90c253c730..47f986ea48 100644
--- a/test/runtime/samples/if-block-else-partial-outro/main.html
+++ b/test/runtime/samples/if-block-else-partial-outro/main.svelte
@@ -2,7 +2,7 @@
 	export let y = false;
 	export let x = 'x';
 
-	import Foo from './Foo.html';
+	import Foo from './Foo.svelte';
 </script>
 
 {#if y}
diff --git a/test/runtime/samples/if-block-else/main.html b/test/runtime/samples/if-block-else/main.svelte
similarity index 100%
rename from test/runtime/samples/if-block-else/main.html
rename to test/runtime/samples/if-block-else/main.svelte
diff --git a/test/runtime/samples/if-block-elseif-no-else/main.html b/test/runtime/samples/if-block-elseif-no-else/main.svelte
similarity index 100%
rename from test/runtime/samples/if-block-elseif-no-else/main.html
rename to test/runtime/samples/if-block-elseif-no-else/main.svelte
diff --git a/test/runtime/samples/if-block-elseif-text/main.html b/test/runtime/samples/if-block-elseif-text/main.svelte
similarity index 100%
rename from test/runtime/samples/if-block-elseif-text/main.html
rename to test/runtime/samples/if-block-elseif-text/main.svelte
diff --git a/test/runtime/samples/if-block-elseif/main.html b/test/runtime/samples/if-block-elseif/main.svelte
similarity index 100%
rename from test/runtime/samples/if-block-elseif/main.html
rename to test/runtime/samples/if-block-elseif/main.svelte
diff --git a/test/runtime/samples/if-block-expression/main.html b/test/runtime/samples/if-block-expression/main.svelte
similarity index 100%
rename from test/runtime/samples/if-block-expression/main.html
rename to test/runtime/samples/if-block-expression/main.svelte
diff --git a/test/runtime/samples/if-block-first/main.html b/test/runtime/samples/if-block-first/main.svelte
similarity index 100%
rename from test/runtime/samples/if-block-first/main.html
rename to test/runtime/samples/if-block-first/main.svelte
diff --git a/test/runtime/samples/if-block-no-outro-else-with-outro/Widget.html b/test/runtime/samples/if-block-no-outro-else-with-outro/Widget.svelte
similarity index 100%
rename from test/runtime/samples/if-block-no-outro-else-with-outro/Widget.html
rename to test/runtime/samples/if-block-no-outro-else-with-outro/Widget.svelte
diff --git a/test/runtime/samples/if-block-no-outro-else-with-outro/main.html b/test/runtime/samples/if-block-no-outro-else-with-outro/main.svelte
similarity index 77%
rename from test/runtime/samples/if-block-no-outro-else-with-outro/main.html
rename to test/runtime/samples/if-block-no-outro-else-with-outro/main.svelte
index 2007bf2ea2..e32a7a52cb 100644
--- a/test/runtime/samples/if-block-no-outro-else-with-outro/main.html
+++ b/test/runtime/samples/if-block-no-outro-else-with-outro/main.svelte
@@ -2,7 +2,7 @@
 	export let foo;
 	export let x = 'x';
 
-	import Widget from './Widget.html';
+	import Widget from './Widget.svelte';
 </script>
 
 {#if foo}
diff --git a/test/runtime/samples/if-block-or/main.html b/test/runtime/samples/if-block-or/main.svelte
similarity index 100%
rename from test/runtime/samples/if-block-or/main.html
rename to test/runtime/samples/if-block-or/main.svelte
diff --git a/test/runtime/samples/if-block-outro-nested-else/Component.html b/test/runtime/samples/if-block-outro-nested-else/Component.svelte
similarity index 100%
rename from test/runtime/samples/if-block-outro-nested-else/Component.html
rename to test/runtime/samples/if-block-outro-nested-else/Component.svelte
diff --git a/test/runtime/samples/if-block-outro-nested-else/main.html b/test/runtime/samples/if-block-outro-nested-else/main.svelte
similarity index 73%
rename from test/runtime/samples/if-block-outro-nested-else/main.html
rename to test/runtime/samples/if-block-outro-nested-else/main.svelte
index c10f861a6c..3937998c40 100644
--- a/test/runtime/samples/if-block-outro-nested-else/main.html
+++ b/test/runtime/samples/if-block-outro-nested-else/main.svelte
@@ -1,7 +1,7 @@
 <script>
 	export let foo = true;
 
-	import Component from './Component.html';
+	import Component from './Component.svelte';
 </script>
 
 {#if foo}
diff --git a/test/runtime/samples/if-block-outro-unique-select-block-type/Component.html b/test/runtime/samples/if-block-outro-unique-select-block-type/Component.svelte
similarity index 100%
rename from test/runtime/samples/if-block-outro-unique-select-block-type/Component.html
rename to test/runtime/samples/if-block-outro-unique-select-block-type/Component.svelte
diff --git a/test/runtime/samples/if-block-outro-unique-select-block-type/main.html b/test/runtime/samples/if-block-outro-unique-select-block-type/main.svelte
similarity index 76%
rename from test/runtime/samples/if-block-outro-unique-select-block-type/main.html
rename to test/runtime/samples/if-block-outro-unique-select-block-type/main.svelte
index 77b3a6dfe3..0579a562eb 100644
--- a/test/runtime/samples/if-block-outro-unique-select-block-type/main.html
+++ b/test/runtime/samples/if-block-outro-unique-select-block-type/main.svelte
@@ -1,7 +1,7 @@
 <script>
 	export let foo = true;
 
-	import Component from './Component.html';
+	import Component from './Component.svelte';
 </script>
 
 {#if foo}
diff --git a/test/runtime/samples/if-block-widget/Widget.html b/test/runtime/samples/if-block-widget/Widget.svelte
similarity index 100%
rename from test/runtime/samples/if-block-widget/Widget.html
rename to test/runtime/samples/if-block-widget/Widget.svelte
diff --git a/test/runtime/samples/if-block-widget/main.html b/test/runtime/samples/if-block-widget/main.svelte
similarity index 69%
rename from test/runtime/samples/if-block-widget/main.html
rename to test/runtime/samples/if-block-widget/main.svelte
index 12996bbcd4..fef00e276c 100644
--- a/test/runtime/samples/if-block-widget/main.html
+++ b/test/runtime/samples/if-block-widget/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Widget from './Widget.html';
+	import Widget from './Widget.svelte';
 
 	export let visible;
 </script>
diff --git a/test/runtime/samples/if-block/main.html b/test/runtime/samples/if-block/main.svelte
similarity index 100%
rename from test/runtime/samples/if-block/main.html
rename to test/runtime/samples/if-block/main.svelte
diff --git a/test/runtime/samples/if-in-keyed-each/main.html b/test/runtime/samples/if-in-keyed-each/main.svelte
similarity index 100%
rename from test/runtime/samples/if-in-keyed-each/main.html
rename to test/runtime/samples/if-in-keyed-each/main.svelte
diff --git a/test/runtime/samples/ignore-unchanged-attribute-compound/main.html b/test/runtime/samples/ignore-unchanged-attribute-compound/main.svelte
similarity index 100%
rename from test/runtime/samples/ignore-unchanged-attribute-compound/main.html
rename to test/runtime/samples/ignore-unchanged-attribute-compound/main.svelte
diff --git a/test/runtime/samples/ignore-unchanged-attribute/main.html b/test/runtime/samples/ignore-unchanged-attribute/main.svelte
similarity index 100%
rename from test/runtime/samples/ignore-unchanged-attribute/main.html
rename to test/runtime/samples/ignore-unchanged-attribute/main.svelte
diff --git a/test/runtime/samples/ignore-unchanged-raw/main.html b/test/runtime/samples/ignore-unchanged-raw/main.svelte
similarity index 100%
rename from test/runtime/samples/ignore-unchanged-raw/main.html
rename to test/runtime/samples/ignore-unchanged-raw/main.svelte
diff --git a/test/runtime/samples/ignore-unchanged-tag/main.html b/test/runtime/samples/ignore-unchanged-tag/main.svelte
similarity index 100%
rename from test/runtime/samples/ignore-unchanged-tag/main.html
rename to test/runtime/samples/ignore-unchanged-tag/main.svelte
diff --git a/test/runtime/samples/immutable-nested/Nested.html b/test/runtime/samples/immutable-nested/Nested.svelte
similarity index 100%
rename from test/runtime/samples/immutable-nested/Nested.html
rename to test/runtime/samples/immutable-nested/Nested.svelte
diff --git a/test/runtime/samples/immutable-nested/main.html b/test/runtime/samples/immutable-nested/main.svelte
similarity index 68%
rename from test/runtime/samples/immutable-nested/main.html
rename to test/runtime/samples/immutable-nested/main.svelte
index aa8efa9ebc..e50055be0c 100644
--- a/test/runtime/samples/immutable-nested/main.html
+++ b/test/runtime/samples/immutable-nested/main.svelte
@@ -1,7 +1,7 @@
 <script>
 	export let nested;
 
-	import Nested from './Nested.html';
+	import Nested from './Nested.svelte';
 </script>
 
 <div>
diff --git a/test/runtime/samples/immutable-option/main.html b/test/runtime/samples/immutable-option/main.svelte
similarity index 100%
rename from test/runtime/samples/immutable-option/main.html
rename to test/runtime/samples/immutable-option/main.svelte
diff --git a/test/runtime/samples/immutable-svelte-meta-false/main.html b/test/runtime/samples/immutable-svelte-meta-false/main.svelte
similarity index 100%
rename from test/runtime/samples/immutable-svelte-meta-false/main.html
rename to test/runtime/samples/immutable-svelte-meta-false/main.svelte
diff --git a/test/runtime/samples/immutable-svelte-meta/main.html b/test/runtime/samples/immutable-svelte-meta/main.svelte
similarity index 100%
rename from test/runtime/samples/immutable-svelte-meta/main.html
rename to test/runtime/samples/immutable-svelte-meta/main.svelte
diff --git a/test/runtime/samples/imported-renamed-components/ComponentOne.html b/test/runtime/samples/imported-renamed-components/ComponentOne.svelte
similarity index 100%
rename from test/runtime/samples/imported-renamed-components/ComponentOne.html
rename to test/runtime/samples/imported-renamed-components/ComponentOne.svelte
diff --git a/test/runtime/samples/imported-renamed-components/ComponentTwo.html b/test/runtime/samples/imported-renamed-components/ComponentTwo.svelte
similarity index 100%
rename from test/runtime/samples/imported-renamed-components/ComponentTwo.html
rename to test/runtime/samples/imported-renamed-components/ComponentTwo.svelte
diff --git a/test/runtime/samples/imported-renamed-components/main.html b/test/runtime/samples/imported-renamed-components/main.svelte
similarity index 59%
rename from test/runtime/samples/imported-renamed-components/main.html
rename to test/runtime/samples/imported-renamed-components/main.svelte
index 9c6efdb230..9055a9e9a5 100644
--- a/test/runtime/samples/imported-renamed-components/main.html
+++ b/test/runtime/samples/imported-renamed-components/main.svelte
@@ -1,6 +1,6 @@
 <script>
-	import ComponentOne from './ComponentOne.html';
-	import ComponentTwo from './ComponentTwo.html';
+	import ComponentOne from './ComponentOne.svelte';
+	import ComponentTwo from './ComponentTwo.svelte';
 
 	const RenamedComponentOne = ComponentOne;
 	const RenamedComponentTwo = ComponentTwo;
diff --git a/test/runtime/samples/initial-state-assign/main.html b/test/runtime/samples/initial-state-assign/main.svelte
similarity index 100%
rename from test/runtime/samples/initial-state-assign/main.html
rename to test/runtime/samples/initial-state-assign/main.svelte
diff --git a/test/runtime/samples/inline-expressions/main.html b/test/runtime/samples/inline-expressions/main.svelte
similarity index 100%
rename from test/runtime/samples/inline-expressions/main.html
rename to test/runtime/samples/inline-expressions/main.svelte
diff --git a/test/runtime/samples/input-list/main.html b/test/runtime/samples/input-list/main.svelte
similarity index 100%
rename from test/runtime/samples/input-list/main.html
rename to test/runtime/samples/input-list/main.svelte
diff --git a/test/runtime/samples/instrumentation-script-destructuring/main.html b/test/runtime/samples/instrumentation-script-destructuring/main.svelte
similarity index 100%
rename from test/runtime/samples/instrumentation-script-destructuring/main.html
rename to test/runtime/samples/instrumentation-script-destructuring/main.svelte
diff --git a/test/runtime/samples/instrumentation-script-loop-scope/main.html b/test/runtime/samples/instrumentation-script-loop-scope/main.svelte
similarity index 100%
rename from test/runtime/samples/instrumentation-script-loop-scope/main.html
rename to test/runtime/samples/instrumentation-script-loop-scope/main.svelte
diff --git a/test/runtime/samples/instrumentation-script-multiple-assignments/main.html b/test/runtime/samples/instrumentation-script-multiple-assignments/main.svelte
similarity index 100%
rename from test/runtime/samples/instrumentation-script-multiple-assignments/main.html
rename to test/runtime/samples/instrumentation-script-multiple-assignments/main.svelte
diff --git a/test/runtime/samples/instrumentation-script-update/main.html b/test/runtime/samples/instrumentation-script-update/main.svelte
similarity index 100%
rename from test/runtime/samples/instrumentation-script-update/main.html
rename to test/runtime/samples/instrumentation-script-update/main.svelte
diff --git a/test/runtime/samples/instrumentation-template-destructuring/main.html b/test/runtime/samples/instrumentation-template-destructuring/main.svelte
similarity index 100%
rename from test/runtime/samples/instrumentation-template-destructuring/main.html
rename to test/runtime/samples/instrumentation-template-destructuring/main.svelte
diff --git a/test/runtime/samples/instrumentation-template-loop-scope/main.html b/test/runtime/samples/instrumentation-template-loop-scope/main.svelte
similarity index 100%
rename from test/runtime/samples/instrumentation-template-loop-scope/main.html
rename to test/runtime/samples/instrumentation-template-loop-scope/main.svelte
diff --git a/test/runtime/samples/instrumentation-template-multiple-assignments/main.html b/test/runtime/samples/instrumentation-template-multiple-assignments/main.svelte
similarity index 100%
rename from test/runtime/samples/instrumentation-template-multiple-assignments/main.html
rename to test/runtime/samples/instrumentation-template-multiple-assignments/main.svelte
diff --git a/test/runtime/samples/instrumentation-template-update/main.html b/test/runtime/samples/instrumentation-template-update/main.svelte
similarity index 100%
rename from test/runtime/samples/instrumentation-template-update/main.html
rename to test/runtime/samples/instrumentation-template-update/main.svelte
diff --git a/test/runtime/samples/internal-state/Foo.html b/test/runtime/samples/internal-state/Foo.svelte
similarity index 100%
rename from test/runtime/samples/internal-state/Foo.html
rename to test/runtime/samples/internal-state/Foo.svelte
diff --git a/test/runtime/samples/internal-state/main.html b/test/runtime/samples/internal-state/main.html
deleted file mode 100644
index 81151cea80..0000000000
--- a/test/runtime/samples/internal-state/main.html
+++ /dev/null
@@ -1,9 +0,0 @@
-<script>
-	import Foo from './Foo.html';
-	
-	let x = 2;
-</script>
-
-<Foo internal={x}/>
-
-<button on:click="{() => x += 1}">click me</button>
\ No newline at end of file
diff --git a/test/runtime/samples/internal-state/main.svelte b/test/runtime/samples/internal-state/main.svelte
new file mode 100644
index 0000000000..594ab3c837
--- /dev/null
+++ b/test/runtime/samples/internal-state/main.svelte
@@ -0,0 +1,9 @@
+<script>
+	import Foo from './Foo.svelte';
+	
+	let x = 2;
+</script>
+
+<Foo internal={x}/>
+
+<button on:click="{() => x += 1}">click me</button>
\ No newline at end of file
diff --git a/test/runtime/samples/lifecycle-events/main.html b/test/runtime/samples/lifecycle-events/main.svelte
similarity index 100%
rename from test/runtime/samples/lifecycle-events/main.html
rename to test/runtime/samples/lifecycle-events/main.svelte
diff --git a/test/runtime/samples/lifecycle-next-tick/main.html b/test/runtime/samples/lifecycle-next-tick/main.svelte
similarity index 100%
rename from test/runtime/samples/lifecycle-next-tick/main.html
rename to test/runtime/samples/lifecycle-next-tick/main.svelte
diff --git a/test/runtime/samples/lifecycle-render-order/main.html b/test/runtime/samples/lifecycle-render-order/main.svelte
similarity index 100%
rename from test/runtime/samples/lifecycle-render-order/main.html
rename to test/runtime/samples/lifecycle-render-order/main.svelte
diff --git a/test/runtime/samples/module-context-with-instance-script/main.html b/test/runtime/samples/module-context-with-instance-script/main.svelte
similarity index 100%
rename from test/runtime/samples/module-context-with-instance-script/main.html
rename to test/runtime/samples/module-context-with-instance-script/main.svelte
diff --git a/test/runtime/samples/module-context/main.html b/test/runtime/samples/module-context/main.svelte
similarity index 100%
rename from test/runtime/samples/module-context/main.html
rename to test/runtime/samples/module-context/main.svelte
diff --git a/test/runtime/samples/mutation-tracking-across-sibling-scopes/main.html b/test/runtime/samples/mutation-tracking-across-sibling-scopes/main.svelte
similarity index 100%
rename from test/runtime/samples/mutation-tracking-across-sibling-scopes/main.html
rename to test/runtime/samples/mutation-tracking-across-sibling-scopes/main.svelte
diff --git a/test/runtime/samples/names-deconflicted-nested/main.html b/test/runtime/samples/names-deconflicted-nested/main.svelte
similarity index 100%
rename from test/runtime/samples/names-deconflicted-nested/main.html
rename to test/runtime/samples/names-deconflicted-nested/main.svelte
diff --git a/test/runtime/samples/names-deconflicted/Widget.html b/test/runtime/samples/names-deconflicted/Widget.svelte
similarity index 100%
rename from test/runtime/samples/names-deconflicted/Widget.html
rename to test/runtime/samples/names-deconflicted/Widget.svelte
diff --git a/test/runtime/samples/names-deconflicted/main.html b/test/runtime/samples/names-deconflicted/main.svelte
similarity index 82%
rename from test/runtime/samples/names-deconflicted/main.html
rename to test/runtime/samples/names-deconflicted/main.svelte
index f2c47a7718..60e3ea1320 100644
--- a/test/runtime/samples/names-deconflicted/main.html
+++ b/test/runtime/samples/names-deconflicted/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Widget from './Widget.html';
+	import Widget from './Widget.svelte';
 
 	export let widgets = [
 		{ name: 'foo' },
diff --git a/test/runtime/samples/nbsp/main.html b/test/runtime/samples/nbsp/main.svelte
similarity index 100%
rename from test/runtime/samples/nbsp/main.html
rename to test/runtime/samples/nbsp/main.svelte
diff --git a/test/runtime/samples/nested-transition-detach-each/main.html b/test/runtime/samples/nested-transition-detach-each/main.svelte
similarity index 100%
rename from test/runtime/samples/nested-transition-detach-each/main.html
rename to test/runtime/samples/nested-transition-detach-each/main.svelte
diff --git a/test/runtime/samples/nested-transition-detach-if-false/Folder.html b/test/runtime/samples/nested-transition-detach-if-false/Folder.svelte
similarity index 100%
rename from test/runtime/samples/nested-transition-detach-if-false/Folder.html
rename to test/runtime/samples/nested-transition-detach-if-false/Folder.svelte
diff --git a/test/runtime/samples/nested-transition-detach-if-false/main.html b/test/runtime/samples/nested-transition-detach-if-false/main.html
deleted file mode 100644
index d52c56c5cf..0000000000
--- a/test/runtime/samples/nested-transition-detach-if-false/main.html
+++ /dev/null
@@ -1,7 +0,0 @@
-<script>
-	export let folder;
-
-	import Folder from './Folder.html';
-</script>
-
-<Folder bind:this={folder} dir="a"/>
\ No newline at end of file
diff --git a/test/runtime/samples/nested-transition-detach-if-false/main.svelte b/test/runtime/samples/nested-transition-detach-if-false/main.svelte
new file mode 100644
index 0000000000..2a7a4b49bf
--- /dev/null
+++ b/test/runtime/samples/nested-transition-detach-if-false/main.svelte
@@ -0,0 +1,7 @@
+<script>
+	export let folder;
+
+	import Folder from './Folder.svelte';
+</script>
+
+<Folder bind:this={folder} dir="a"/>
\ No newline at end of file
diff --git a/test/runtime/samples/nested-transition-if-block-not-remounted/Span.html b/test/runtime/samples/nested-transition-if-block-not-remounted/Span.svelte
similarity index 100%
rename from test/runtime/samples/nested-transition-if-block-not-remounted/Span.html
rename to test/runtime/samples/nested-transition-if-block-not-remounted/Span.svelte
diff --git a/test/runtime/samples/nested-transition-if-block-not-remounted/main.html b/test/runtime/samples/nested-transition-if-block-not-remounted/main.svelte
similarity index 75%
rename from test/runtime/samples/nested-transition-if-block-not-remounted/main.html
rename to test/runtime/samples/nested-transition-if-block-not-remounted/main.svelte
index 373d3d0485..e6456a86f6 100644
--- a/test/runtime/samples/nested-transition-if-block-not-remounted/main.html
+++ b/test/runtime/samples/nested-transition-if-block-not-remounted/main.svelte
@@ -1,7 +1,7 @@
 <script>
 	export let x;
 
-	import Span from './Span.html';
+	import Span from './Span.svelte';
 </script>
 
 <div>
diff --git a/test/runtime/samples/noscript-removal/main.html b/test/runtime/samples/noscript-removal/main.svelte
similarity index 100%
rename from test/runtime/samples/noscript-removal/main.html
rename to test/runtime/samples/noscript-removal/main.svelte
diff --git a/test/runtime/samples/ondestroy-before-cleanup/Top.html b/test/runtime/samples/ondestroy-before-cleanup/Top.svelte
similarity index 100%
rename from test/runtime/samples/ondestroy-before-cleanup/Top.html
rename to test/runtime/samples/ondestroy-before-cleanup/Top.svelte
diff --git a/test/runtime/samples/ondestroy-before-cleanup/main.html b/test/runtime/samples/ondestroy-before-cleanup/main.svelte
similarity index 74%
rename from test/runtime/samples/ondestroy-before-cleanup/main.html
rename to test/runtime/samples/ondestroy-before-cleanup/main.svelte
index 34053dd613..efd940053e 100644
--- a/test/runtime/samples/ondestroy-before-cleanup/main.html
+++ b/test/runtime/samples/ondestroy-before-cleanup/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Top from './Top.html';
+	import Top from './Top.svelte';
 
 	export let top;
 	export let visible = true;
diff --git a/test/runtime/samples/onmount-async/main.html b/test/runtime/samples/onmount-async/main.svelte
similarity index 100%
rename from test/runtime/samples/onmount-async/main.html
rename to test/runtime/samples/onmount-async/main.svelte
diff --git a/test/runtime/samples/onmount-fires-when-ready-nested/ParentWidget.html b/test/runtime/samples/onmount-fires-when-ready-nested/ParentWidget.svelte
similarity index 64%
rename from test/runtime/samples/onmount-fires-when-ready-nested/ParentWidget.html
rename to test/runtime/samples/onmount-fires-when-ready-nested/ParentWidget.svelte
index e1dc10c773..5fc663d98f 100644
--- a/test/runtime/samples/onmount-fires-when-ready-nested/ParentWidget.html
+++ b/test/runtime/samples/onmount-fires-when-ready-nested/ParentWidget.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Widget from './Widget.html';
+	import Widget from './Widget.svelte';
 
 	export let foo;
 </script>
diff --git a/test/runtime/samples/onmount-fires-when-ready-nested/Widget.html b/test/runtime/samples/onmount-fires-when-ready-nested/Widget.svelte
similarity index 100%
rename from test/runtime/samples/onmount-fires-when-ready-nested/Widget.html
rename to test/runtime/samples/onmount-fires-when-ready-nested/Widget.svelte
diff --git a/test/runtime/samples/onmount-fires-when-ready-nested/main.html b/test/runtime/samples/onmount-fires-when-ready-nested/main.html
deleted file mode 100644
index 910f63e086..0000000000
--- a/test/runtime/samples/onmount-fires-when-ready-nested/main.html
+++ /dev/null
@@ -1,9 +0,0 @@
-<script>
-	import Widget from './Widget.html';
-	import ParentWidget from './ParentWidget.html';
-</script>
-
-<div>
-	<Widget/>
-	<ParentWidget />
-</div>
diff --git a/test/runtime/samples/onmount-fires-when-ready-nested/main.svelte b/test/runtime/samples/onmount-fires-when-ready-nested/main.svelte
new file mode 100644
index 0000000000..a155293e26
--- /dev/null
+++ b/test/runtime/samples/onmount-fires-when-ready-nested/main.svelte
@@ -0,0 +1,9 @@
+<script>
+	import Widget from './Widget.svelte';
+	import ParentWidget from './ParentWidget.svelte';
+</script>
+
+<div>
+	<Widget/>
+	<ParentWidget />
+</div>
diff --git a/test/runtime/samples/onmount-fires-when-ready/Widget.html b/test/runtime/samples/onmount-fires-when-ready/Widget.svelte
similarity index 100%
rename from test/runtime/samples/onmount-fires-when-ready/Widget.html
rename to test/runtime/samples/onmount-fires-when-ready/Widget.svelte
diff --git a/test/runtime/samples/onmount-fires-when-ready/main.html b/test/runtime/samples/onmount-fires-when-ready/main.svelte
similarity index 70%
rename from test/runtime/samples/onmount-fires-when-ready/main.html
rename to test/runtime/samples/onmount-fires-when-ready/main.svelte
index f2760ecff1..1204ac6719 100644
--- a/test/runtime/samples/onmount-fires-when-ready/main.html
+++ b/test/runtime/samples/onmount-fires-when-ready/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Widget from './Widget.html';
+	import Widget from './Widget.svelte';
 
 	export let foo;
 </script>
diff --git a/test/runtime/samples/onmount-sibling-order/Nested.html b/test/runtime/samples/onmount-sibling-order/Nested.svelte
similarity index 100%
rename from test/runtime/samples/onmount-sibling-order/Nested.html
rename to test/runtime/samples/onmount-sibling-order/Nested.svelte
diff --git a/test/runtime/samples/onmount-sibling-order/main.html b/test/runtime/samples/onmount-sibling-order/main.html
deleted file mode 100644
index e4218aa4b4..0000000000
--- a/test/runtime/samples/onmount-sibling-order/main.html
+++ /dev/null
@@ -1,6 +0,0 @@
-<script>
-	import Nested from './Nested.html';
-</script>
-
-<Nested name='foo'/>
-<Nested name='bar'/>
\ No newline at end of file
diff --git a/test/runtime/samples/onmount-sibling-order/main.svelte b/test/runtime/samples/onmount-sibling-order/main.svelte
new file mode 100644
index 0000000000..3fbf499755
--- /dev/null
+++ b/test/runtime/samples/onmount-sibling-order/main.svelte
@@ -0,0 +1,6 @@
+<script>
+	import Nested from './Nested.svelte';
+</script>
+
+<Nested name='foo'/>
+<Nested name='bar'/>
\ No newline at end of file
diff --git a/test/runtime/samples/option-without-select/main.html b/test/runtime/samples/option-without-select/main.svelte
similarity index 100%
rename from test/runtime/samples/option-without-select/main.html
rename to test/runtime/samples/option-without-select/main.svelte
diff --git a/test/runtime/samples/paren-wrapped-expressions/main.html b/test/runtime/samples/paren-wrapped-expressions/main.svelte
similarity index 100%
rename from test/runtime/samples/paren-wrapped-expressions/main.html
rename to test/runtime/samples/paren-wrapped-expressions/main.svelte
diff --git a/test/runtime/samples/preload/main.html b/test/runtime/samples/preload/main.svelte
similarity index 100%
rename from test/runtime/samples/preload/main.html
rename to test/runtime/samples/preload/main.svelte
diff --git a/test/runtime/samples/prop-not-action/Nested.html b/test/runtime/samples/prop-not-action/Nested.svelte
similarity index 100%
rename from test/runtime/samples/prop-not-action/Nested.html
rename to test/runtime/samples/prop-not-action/Nested.svelte
diff --git a/test/runtime/samples/prop-not-action/main.html b/test/runtime/samples/prop-not-action/main.html
deleted file mode 100644
index c0ddd01e79..0000000000
--- a/test/runtime/samples/prop-not-action/main.html
+++ /dev/null
@@ -1,6 +0,0 @@
-<script>
-	import Nested from './Nested.html';
-	export let currentUser;
-</script>
-
-<Nested user={currentUser}/>
\ No newline at end of file
diff --git a/test/runtime/samples/prop-not-action/main.svelte b/test/runtime/samples/prop-not-action/main.svelte
new file mode 100644
index 0000000000..e1c40bc070
--- /dev/null
+++ b/test/runtime/samples/prop-not-action/main.svelte
@@ -0,0 +1,6 @@
+<script>
+	import Nested from './Nested.svelte';
+	export let currentUser;
+</script>
+
+<Nested user={currentUser}/>
\ No newline at end of file
diff --git a/test/runtime/samples/prop-without-semicolon-b/main.html b/test/runtime/samples/prop-without-semicolon-b/main.svelte
similarity index 100%
rename from test/runtime/samples/prop-without-semicolon-b/main.html
rename to test/runtime/samples/prop-without-semicolon-b/main.svelte
diff --git a/test/runtime/samples/prop-without-semicolon/main.html b/test/runtime/samples/prop-without-semicolon/main.svelte
similarity index 100%
rename from test/runtime/samples/prop-without-semicolon/main.html
rename to test/runtime/samples/prop-without-semicolon/main.svelte
diff --git a/test/runtime/samples/raw-anchor-first-child/main.html b/test/runtime/samples/raw-anchor-first-child/main.svelte
similarity index 100%
rename from test/runtime/samples/raw-anchor-first-child/main.html
rename to test/runtime/samples/raw-anchor-first-child/main.svelte
diff --git a/test/runtime/samples/raw-anchor-first-last-child/main.html b/test/runtime/samples/raw-anchor-first-last-child/main.svelte
similarity index 100%
rename from test/runtime/samples/raw-anchor-first-last-child/main.html
rename to test/runtime/samples/raw-anchor-first-last-child/main.svelte
diff --git a/test/runtime/samples/raw-anchor-last-child/main.html b/test/runtime/samples/raw-anchor-last-child/main.svelte
similarity index 100%
rename from test/runtime/samples/raw-anchor-last-child/main.html
rename to test/runtime/samples/raw-anchor-last-child/main.svelte
diff --git a/test/runtime/samples/raw-anchor-next-previous-sibling/main.html b/test/runtime/samples/raw-anchor-next-previous-sibling/main.svelte
similarity index 100%
rename from test/runtime/samples/raw-anchor-next-previous-sibling/main.html
rename to test/runtime/samples/raw-anchor-next-previous-sibling/main.svelte
diff --git a/test/runtime/samples/raw-anchor-next-sibling/main.html b/test/runtime/samples/raw-anchor-next-sibling/main.svelte
similarity index 100%
rename from test/runtime/samples/raw-anchor-next-sibling/main.html
rename to test/runtime/samples/raw-anchor-next-sibling/main.svelte
diff --git a/test/runtime/samples/raw-anchor-previous-sibling/main.html b/test/runtime/samples/raw-anchor-previous-sibling/main.svelte
similarity index 100%
rename from test/runtime/samples/raw-anchor-previous-sibling/main.html
rename to test/runtime/samples/raw-anchor-previous-sibling/main.svelte
diff --git a/test/runtime/samples/raw-mustaches-preserved/main.html b/test/runtime/samples/raw-mustaches-preserved/main.svelte
similarity index 100%
rename from test/runtime/samples/raw-mustaches-preserved/main.html
rename to test/runtime/samples/raw-mustaches-preserved/main.svelte
diff --git a/test/runtime/samples/raw-mustaches/main.html b/test/runtime/samples/raw-mustaches/main.svelte
similarity index 100%
rename from test/runtime/samples/raw-mustaches/main.html
rename to test/runtime/samples/raw-mustaches/main.svelte
diff --git a/test/runtime/samples/reactive-function/main.html b/test/runtime/samples/reactive-function/main.svelte
similarity index 100%
rename from test/runtime/samples/reactive-function/main.html
rename to test/runtime/samples/reactive-function/main.svelte
diff --git a/test/runtime/samples/reactive-values-deconflicted/main.html b/test/runtime/samples/reactive-values-deconflicted/main.svelte
similarity index 100%
rename from test/runtime/samples/reactive-values-deconflicted/main.html
rename to test/runtime/samples/reactive-values-deconflicted/main.svelte
diff --git a/test/runtime/samples/reactive-values-function-dependency/main.html b/test/runtime/samples/reactive-values-function-dependency/main.svelte
similarity index 100%
rename from test/runtime/samples/reactive-values-function-dependency/main.html
rename to test/runtime/samples/reactive-values-function-dependency/main.svelte
diff --git a/test/runtime/samples/reactive-values-implicit/main.html b/test/runtime/samples/reactive-values-implicit/main.svelte
similarity index 100%
rename from test/runtime/samples/reactive-values-implicit/main.html
rename to test/runtime/samples/reactive-values-implicit/main.svelte
diff --git a/test/runtime/samples/reactive-values-non-cyclical/main.html b/test/runtime/samples/reactive-values-non-cyclical/main.svelte
similarity index 100%
rename from test/runtime/samples/reactive-values-non-cyclical/main.html
rename to test/runtime/samples/reactive-values-non-cyclical/main.svelte
diff --git a/test/runtime/samples/reactive-values-readonly/main.html b/test/runtime/samples/reactive-values-readonly/main.svelte
similarity index 100%
rename from test/runtime/samples/reactive-values-readonly/main.html
rename to test/runtime/samples/reactive-values-readonly/main.svelte
diff --git a/test/runtime/samples/reactive-values-second-order/main.html b/test/runtime/samples/reactive-values-second-order/main.svelte
similarity index 100%
rename from test/runtime/samples/reactive-values-second-order/main.html
rename to test/runtime/samples/reactive-values-second-order/main.svelte
diff --git a/test/runtime/samples/reactive-values-self-dependency/main.html b/test/runtime/samples/reactive-values-self-dependency/main.svelte
similarity index 100%
rename from test/runtime/samples/reactive-values-self-dependency/main.html
rename to test/runtime/samples/reactive-values-self-dependency/main.svelte
diff --git a/test/runtime/samples/reactive-values/main.html b/test/runtime/samples/reactive-values/main.svelte
similarity index 100%
rename from test/runtime/samples/reactive-values/main.html
rename to test/runtime/samples/reactive-values/main.svelte
diff --git a/test/runtime/samples/script-style-non-top-level/main.html b/test/runtime/samples/script-style-non-top-level/main.svelte
similarity index 100%
rename from test/runtime/samples/script-style-non-top-level/main.html
rename to test/runtime/samples/script-style-non-top-level/main.svelte
diff --git a/test/runtime/samples/select-bind-array/main.html b/test/runtime/samples/select-bind-array/main.svelte
similarity index 100%
rename from test/runtime/samples/select-bind-array/main.html
rename to test/runtime/samples/select-bind-array/main.svelte
diff --git a/test/runtime/samples/select-bind-in-array/main.html b/test/runtime/samples/select-bind-in-array/main.svelte
similarity index 100%
rename from test/runtime/samples/select-bind-in-array/main.html
rename to test/runtime/samples/select-bind-in-array/main.svelte
diff --git a/test/runtime/samples/select-change-handler/main.html b/test/runtime/samples/select-change-handler/main.svelte
similarity index 100%
rename from test/runtime/samples/select-change-handler/main.html
rename to test/runtime/samples/select-change-handler/main.svelte
diff --git a/test/runtime/samples/select-no-whitespace/main.html b/test/runtime/samples/select-no-whitespace/main.svelte
similarity index 100%
rename from test/runtime/samples/select-no-whitespace/main.html
rename to test/runtime/samples/select-no-whitespace/main.svelte
diff --git a/test/runtime/samples/select-one-way-bind-object/main.html b/test/runtime/samples/select-one-way-bind-object/main.svelte
similarity index 100%
rename from test/runtime/samples/select-one-way-bind-object/main.html
rename to test/runtime/samples/select-one-way-bind-object/main.svelte
diff --git a/test/runtime/samples/select-one-way-bind/main.html b/test/runtime/samples/select-one-way-bind/main.svelte
similarity index 100%
rename from test/runtime/samples/select-one-way-bind/main.html
rename to test/runtime/samples/select-one-way-bind/main.svelte
diff --git a/test/runtime/samples/select-props/main.html b/test/runtime/samples/select-props/main.svelte
similarity index 100%
rename from test/runtime/samples/select-props/main.html
rename to test/runtime/samples/select-props/main.svelte
diff --git a/test/runtime/samples/select/main.html b/test/runtime/samples/select/main.svelte
similarity index 100%
rename from test/runtime/samples/select/main.html
rename to test/runtime/samples/select/main.svelte
diff --git a/test/runtime/samples/self-reference-tree/main.html b/test/runtime/samples/self-reference-tree/main.svelte
similarity index 100%
rename from test/runtime/samples/self-reference-tree/main.html
rename to test/runtime/samples/self-reference-tree/main.svelte
diff --git a/test/runtime/samples/self-reference/main.html b/test/runtime/samples/self-reference/main.svelte
similarity index 100%
rename from test/runtime/samples/self-reference/main.html
rename to test/runtime/samples/self-reference/main.svelte
diff --git a/test/runtime/samples/set-after-destroy/main.html b/test/runtime/samples/set-after-destroy/main.svelte
similarity index 100%
rename from test/runtime/samples/set-after-destroy/main.html
rename to test/runtime/samples/set-after-destroy/main.svelte
diff --git a/test/runtime/samples/set-in-oncreate/main.html b/test/runtime/samples/set-in-oncreate/main.svelte
similarity index 100%
rename from test/runtime/samples/set-in-oncreate/main.html
rename to test/runtime/samples/set-in-oncreate/main.svelte
diff --git a/test/runtime/samples/set-in-onstate-dedupes-renders/Widget.html b/test/runtime/samples/set-in-onstate-dedupes-renders/Widget.svelte
similarity index 100%
rename from test/runtime/samples/set-in-onstate-dedupes-renders/Widget.html
rename to test/runtime/samples/set-in-onstate-dedupes-renders/Widget.svelte
diff --git a/test/runtime/samples/set-in-onstate-dedupes-renders/main.html b/test/runtime/samples/set-in-onstate-dedupes-renders/main.svelte
similarity index 83%
rename from test/runtime/samples/set-in-onstate-dedupes-renders/main.html
rename to test/runtime/samples/set-in-onstate-dedupes-renders/main.svelte
index d6fe905c3b..cf87944bb8 100644
--- a/test/runtime/samples/set-in-onstate-dedupes-renders/main.html
+++ b/test/runtime/samples/set-in-onstate-dedupes-renders/main.svelte
@@ -1,7 +1,7 @@
 <script>
 	import { beforeUpdate } from 'svelte';
 
-	import Widget from './Widget.html';
+	import Widget from './Widget.svelte';
 
 	export let foo = { x: 1 };
 	export let bar = { x: 1 };
diff --git a/test/runtime/samples/set-in-onstate/main.html b/test/runtime/samples/set-in-onstate/main.svelte
similarity index 100%
rename from test/runtime/samples/set-in-onstate/main.html
rename to test/runtime/samples/set-in-onstate/main.svelte
diff --git a/test/runtime/samples/set-null-text-node/main.html b/test/runtime/samples/set-null-text-node/main.svelte
similarity index 100%
rename from test/runtime/samples/set-null-text-node/main.html
rename to test/runtime/samples/set-null-text-node/main.svelte
diff --git a/test/runtime/samples/set-prevents-loop/Foo.html b/test/runtime/samples/set-prevents-loop/Foo.svelte
similarity index 100%
rename from test/runtime/samples/set-prevents-loop/Foo.html
rename to test/runtime/samples/set-prevents-loop/Foo.svelte
diff --git a/test/runtime/samples/set-prevents-loop/main.html b/test/runtime/samples/set-prevents-loop/main.svelte
similarity index 81%
rename from test/runtime/samples/set-prevents-loop/main.html
rename to test/runtime/samples/set-prevents-loop/main.svelte
index 890e81db7b..f946037ee6 100644
--- a/test/runtime/samples/set-prevents-loop/main.html
+++ b/test/runtime/samples/set-prevents-loop/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Foo from './Foo.html';
+	import Foo from './Foo.svelte';
 
 	export let visible = true;
 	export let answer = 42;
diff --git a/test/runtime/samples/set-undefined-attr/main.html b/test/runtime/samples/set-undefined-attr/main.svelte
similarity index 100%
rename from test/runtime/samples/set-undefined-attr/main.html
rename to test/runtime/samples/set-undefined-attr/main.svelte
diff --git a/test/runtime/samples/sigil-component-attribute/Widget.html b/test/runtime/samples/sigil-component-attribute/Widget.svelte
similarity index 100%
rename from test/runtime/samples/sigil-component-attribute/Widget.html
rename to test/runtime/samples/sigil-component-attribute/Widget.svelte
diff --git a/test/runtime/samples/sigil-component-attribute/main.html b/test/runtime/samples/sigil-component-attribute/main.svelte
similarity index 65%
rename from test/runtime/samples/sigil-component-attribute/main.html
rename to test/runtime/samples/sigil-component-attribute/main.svelte
index 93ff1b8fe6..07c36d3a41 100644
--- a/test/runtime/samples/sigil-component-attribute/main.html
+++ b/test/runtime/samples/sigil-component-attribute/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Widget from './Widget.html';
+	import Widget from './Widget.svelte';
 	export let foo;
 </script>
 
diff --git a/test/runtime/samples/sigil-static-#/main.html b/test/runtime/samples/sigil-static-#/main.svelte
similarity index 100%
rename from test/runtime/samples/sigil-static-#/main.html
rename to test/runtime/samples/sigil-static-#/main.svelte
diff --git a/test/runtime/samples/sigil-static-@/main.html b/test/runtime/samples/sigil-static-@/main.svelte
similarity index 100%
rename from test/runtime/samples/sigil-static-@/main.html
rename to test/runtime/samples/sigil-static-@/main.svelte
diff --git a/test/runtime/samples/single-static-element/main.html b/test/runtime/samples/single-static-element/main.svelte
similarity index 100%
rename from test/runtime/samples/single-static-element/main.html
rename to test/runtime/samples/single-static-element/main.svelte
diff --git a/test/runtime/samples/single-text-node/main.html b/test/runtime/samples/single-text-node/main.svelte
similarity index 100%
rename from test/runtime/samples/single-text-node/main.html
rename to test/runtime/samples/single-text-node/main.svelte
diff --git a/test/runtime/samples/slot-in-custom-element/main.html b/test/runtime/samples/slot-in-custom-element/main.svelte
similarity index 100%
rename from test/runtime/samples/slot-in-custom-element/main.html
rename to test/runtime/samples/slot-in-custom-element/main.svelte
diff --git a/test/runtime/samples/spread-component-dynamic-undefined/main.html b/test/runtime/samples/spread-component-dynamic-undefined/main.svelte
similarity index 100%
rename from test/runtime/samples/spread-component-dynamic-undefined/main.html
rename to test/runtime/samples/spread-component-dynamic-undefined/main.svelte
diff --git a/test/runtime/samples/spread-component-dynamic/Foo.html b/test/runtime/samples/spread-component-dynamic/Foo.svelte
similarity index 100%
rename from test/runtime/samples/spread-component-dynamic/Foo.html
rename to test/runtime/samples/spread-component-dynamic/Foo.svelte
diff --git a/test/runtime/samples/spread-component-dynamic/main.html b/test/runtime/samples/spread-component-dynamic/main.html
deleted file mode 100644
index 4b83ee5307..0000000000
--- a/test/runtime/samples/spread-component-dynamic/main.html
+++ /dev/null
@@ -1,7 +0,0 @@
-<script>
-	import Foo from './Foo.html';
-
-	export let props;
-</script>
-
-<svelte:component this={Foo} {...props} />
\ No newline at end of file
diff --git a/test/runtime/samples/spread-component-dynamic/main.svelte b/test/runtime/samples/spread-component-dynamic/main.svelte
new file mode 100644
index 0000000000..879a5c2cd5
--- /dev/null
+++ b/test/runtime/samples/spread-component-dynamic/main.svelte
@@ -0,0 +1,7 @@
+<script>
+	import Foo from './Foo.svelte';
+
+	export let props;
+</script>
+
+<svelte:component this={Foo} {...props} />
\ No newline at end of file
diff --git a/test/runtime/samples/spread-component-multiple-dependencies/Widget.html b/test/runtime/samples/spread-component-multiple-dependencies/Widget.svelte
similarity index 100%
rename from test/runtime/samples/spread-component-multiple-dependencies/Widget.html
rename to test/runtime/samples/spread-component-multiple-dependencies/Widget.svelte
diff --git a/test/runtime/samples/spread-component-multiple-dependencies/main.html b/test/runtime/samples/spread-component-multiple-dependencies/main.svelte
similarity index 80%
rename from test/runtime/samples/spread-component-multiple-dependencies/main.html
rename to test/runtime/samples/spread-component-multiple-dependencies/main.svelte
index 79ed1d2974..a60043391a 100644
--- a/test/runtime/samples/spread-component-multiple-dependencies/main.html
+++ b/test/runtime/samples/spread-component-multiple-dependencies/main.svelte
@@ -4,7 +4,7 @@
 	export let b = 'b';
 	export let bar = { baz: 'baz' };
 
-	import Widget from './Widget.html';
+	import Widget from './Widget.svelte';
 </script>
 
 <Widget foo={foo ? a : b} {...bar}/>
diff --git a/test/runtime/samples/spread-component-with-bind/Widget.html b/test/runtime/samples/spread-component-with-bind/Widget.svelte
similarity index 100%
rename from test/runtime/samples/spread-component-with-bind/Widget.html
rename to test/runtime/samples/spread-component-with-bind/Widget.svelte
diff --git a/test/runtime/samples/spread-component-with-bind/main.html b/test/runtime/samples/spread-component-with-bind/main.html
deleted file mode 100644
index e4c81624fd..0000000000
--- a/test/runtime/samples/spread-component-with-bind/main.html
+++ /dev/null
@@ -1,8 +0,0 @@
-<script>
-	import Widget from './Widget.html';
-
-	export let props = {};
-	export let x = 'foo';
-</script>
-
-<svelte:component this={Widget} {...props} bind:value={x} />
\ No newline at end of file
diff --git a/test/runtime/samples/spread-component-with-bind/main.svelte b/test/runtime/samples/spread-component-with-bind/main.svelte
new file mode 100644
index 0000000000..98375e2348
--- /dev/null
+++ b/test/runtime/samples/spread-component-with-bind/main.svelte
@@ -0,0 +1,8 @@
+<script>
+	import Widget from './Widget.svelte';
+
+	export let props = {};
+	export let x = 'foo';
+</script>
+
+<svelte:component this={Widget} {...props} bind:value={x} />
\ No newline at end of file
diff --git a/test/runtime/samples/spread-component/Widget.html b/test/runtime/samples/spread-component/Widget.svelte
similarity index 100%
rename from test/runtime/samples/spread-component/Widget.html
rename to test/runtime/samples/spread-component/Widget.svelte
diff --git a/test/runtime/samples/spread-component/main.html b/test/runtime/samples/spread-component/main.svelte
similarity index 69%
rename from test/runtime/samples/spread-component/main.html
rename to test/runtime/samples/spread-component/main.svelte
index 351a7964ef..3ca281903e 100644
--- a/test/runtime/samples/spread-component/main.html
+++ b/test/runtime/samples/spread-component/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Widget from './Widget.html';
+	import Widget from './Widget.svelte';
 
 	export let props;
 </script>
diff --git a/test/runtime/samples/spread-each-component/Nested.html b/test/runtime/samples/spread-each-component/Nested.svelte
similarity index 100%
rename from test/runtime/samples/spread-each-component/Nested.html
rename to test/runtime/samples/spread-each-component/Nested.svelte
diff --git a/test/runtime/samples/spread-each-component/main.html b/test/runtime/samples/spread-each-component/main.svelte
similarity index 65%
rename from test/runtime/samples/spread-each-component/main.html
rename to test/runtime/samples/spread-each-component/main.svelte
index 2124861160..f8c0cebaba 100644
--- a/test/runtime/samples/spread-each-component/main.html
+++ b/test/runtime/samples/spread-each-component/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Nested from './Nested.html';
+	import Nested from './Nested.svelte';
 
 	export let things;
 </script>
diff --git a/test/runtime/samples/spread-each-element/main.html b/test/runtime/samples/spread-each-element/main.svelte
similarity index 100%
rename from test/runtime/samples/spread-each-element/main.html
rename to test/runtime/samples/spread-each-element/main.svelte
diff --git a/test/runtime/samples/spread-element-boolean/main.html b/test/runtime/samples/spread-element-boolean/main.svelte
similarity index 100%
rename from test/runtime/samples/spread-element-boolean/main.html
rename to test/runtime/samples/spread-element-boolean/main.svelte
diff --git a/test/runtime/samples/spread-element-input/main.html b/test/runtime/samples/spread-element-input/main.svelte
similarity index 100%
rename from test/runtime/samples/spread-element-input/main.html
rename to test/runtime/samples/spread-element-input/main.svelte
diff --git a/test/runtime/samples/spread-element-multiple-dependencies/main.html b/test/runtime/samples/spread-element-multiple-dependencies/main.svelte
similarity index 100%
rename from test/runtime/samples/spread-element-multiple-dependencies/main.html
rename to test/runtime/samples/spread-element-multiple-dependencies/main.svelte
diff --git a/test/runtime/samples/spread-element-multiple/main.html b/test/runtime/samples/spread-element-multiple/main.svelte
similarity index 100%
rename from test/runtime/samples/spread-element-multiple/main.html
rename to test/runtime/samples/spread-element-multiple/main.svelte
diff --git a/test/runtime/samples/spread-element/main.html b/test/runtime/samples/spread-element/main.svelte
similarity index 100%
rename from test/runtime/samples/spread-element/main.html
rename to test/runtime/samples/spread-element/main.svelte
diff --git a/test/runtime/samples/spread-own-props/Widget.html b/test/runtime/samples/spread-own-props/Widget.svelte
similarity index 100%
rename from test/runtime/samples/spread-own-props/Widget.html
rename to test/runtime/samples/spread-own-props/Widget.svelte
diff --git a/test/runtime/samples/spread-own-props/main.html b/test/runtime/samples/spread-own-props/main.svelte
similarity index 73%
rename from test/runtime/samples/spread-own-props/main.html
rename to test/runtime/samples/spread-own-props/main.svelte
index 79afded90e..5fbd75d663 100644
--- a/test/runtime/samples/spread-own-props/main.html
+++ b/test/runtime/samples/spread-own-props/main.svelte
@@ -1,7 +1,7 @@
 <svelte:options bind:props/>
 
 <script>
-	import Widget from './Widget.html';
+	import Widget from './Widget.svelte';
 
 	let props;
 </script>
diff --git a/test/runtime/samples/state-deconflicted/main.html b/test/runtime/samples/state-deconflicted/main.svelte
similarity index 100%
rename from test/runtime/samples/state-deconflicted/main.html
rename to test/runtime/samples/state-deconflicted/main.svelte
diff --git a/test/runtime/samples/store-auto-subscribe-implicit/main.html b/test/runtime/samples/store-auto-subscribe-implicit/main.svelte
similarity index 100%
rename from test/runtime/samples/store-auto-subscribe-implicit/main.html
rename to test/runtime/samples/store-auto-subscribe-implicit/main.svelte
diff --git a/test/runtime/samples/store-auto-subscribe-in-each/main.html b/test/runtime/samples/store-auto-subscribe-in-each/main.svelte
similarity index 100%
rename from test/runtime/samples/store-auto-subscribe-in-each/main.html
rename to test/runtime/samples/store-auto-subscribe-in-each/main.svelte
diff --git a/test/runtime/samples/store-auto-subscribe-in-reactive-declaration/main.html b/test/runtime/samples/store-auto-subscribe-in-reactive-declaration/main.svelte
similarity index 100%
rename from test/runtime/samples/store-auto-subscribe-in-reactive-declaration/main.html
rename to test/runtime/samples/store-auto-subscribe-in-reactive-declaration/main.svelte
diff --git a/test/runtime/samples/store-auto-subscribe-in-script/main.html b/test/runtime/samples/store-auto-subscribe-in-script/main.svelte
similarity index 100%
rename from test/runtime/samples/store-auto-subscribe-in-script/main.html
rename to test/runtime/samples/store-auto-subscribe-in-script/main.svelte
diff --git a/test/runtime/samples/store-auto-subscribe/main.html b/test/runtime/samples/store-auto-subscribe/main.svelte
similarity index 100%
rename from test/runtime/samples/store-auto-subscribe/main.html
rename to test/runtime/samples/store-auto-subscribe/main.svelte
diff --git a/test/runtime/samples/store-dev-mode-error/main.html b/test/runtime/samples/store-dev-mode-error/main.svelte
similarity index 100%
rename from test/runtime/samples/store-dev-mode-error/main.html
rename to test/runtime/samples/store-dev-mode-error/main.svelte
diff --git a/test/runtime/samples/store-prevent-user-declarations/main.html b/test/runtime/samples/store-prevent-user-declarations/main.svelte
similarity index 100%
rename from test/runtime/samples/store-prevent-user-declarations/main.html
rename to test/runtime/samples/store-prevent-user-declarations/main.svelte
diff --git a/test/runtime/samples/svg-attributes/main.html b/test/runtime/samples/svg-attributes/main.svelte
similarity index 100%
rename from test/runtime/samples/svg-attributes/main.html
rename to test/runtime/samples/svg-attributes/main.svelte
diff --git a/test/runtime/samples/svg-child-component-declared-namespace-shorthand/Rect.html b/test/runtime/samples/svg-child-component-declared-namespace-shorthand/Rect.svelte
similarity index 100%
rename from test/runtime/samples/svg-child-component-declared-namespace-shorthand/Rect.html
rename to test/runtime/samples/svg-child-component-declared-namespace-shorthand/Rect.svelte
diff --git a/test/runtime/samples/svg-child-component-declared-namespace/main.html b/test/runtime/samples/svg-child-component-declared-namespace-shorthand/main.svelte
similarity index 82%
rename from test/runtime/samples/svg-child-component-declared-namespace/main.html
rename to test/runtime/samples/svg-child-component-declared-namespace-shorthand/main.svelte
index 9e82368dbc..aa65b2b453 100644
--- a/test/runtime/samples/svg-child-component-declared-namespace/main.html
+++ b/test/runtime/samples/svg-child-component-declared-namespace-shorthand/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Rect from './Rect.html';
+	import Rect from './Rect.svelte';
 
 	export let x;
 	export let y;
diff --git a/test/runtime/samples/svg-child-component-declared-namespace/Rect.html b/test/runtime/samples/svg-child-component-declared-namespace/Rect.svelte
similarity index 100%
rename from test/runtime/samples/svg-child-component-declared-namespace/Rect.html
rename to test/runtime/samples/svg-child-component-declared-namespace/Rect.svelte
diff --git a/test/runtime/samples/svg-child-component-declared-namespace-shorthand/main.html b/test/runtime/samples/svg-child-component-declared-namespace/main.svelte
similarity index 82%
rename from test/runtime/samples/svg-child-component-declared-namespace-shorthand/main.html
rename to test/runtime/samples/svg-child-component-declared-namespace/main.svelte
index 9e82368dbc..aa65b2b453 100644
--- a/test/runtime/samples/svg-child-component-declared-namespace-shorthand/main.html
+++ b/test/runtime/samples/svg-child-component-declared-namespace/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Rect from './Rect.html';
+	import Rect from './Rect.svelte';
 
 	export let x;
 	export let y;
diff --git a/test/runtime/samples/svg-class/main.html b/test/runtime/samples/svg-class/main.svelte
similarity index 100%
rename from test/runtime/samples/svg-class/main.html
rename to test/runtime/samples/svg-class/main.svelte
diff --git a/test/runtime/samples/svg-each-block-anchor/main.html b/test/runtime/samples/svg-each-block-anchor/main.svelte
similarity index 100%
rename from test/runtime/samples/svg-each-block-anchor/main.html
rename to test/runtime/samples/svg-each-block-anchor/main.svelte
diff --git a/test/runtime/samples/svg-each-block-namespace/main.html b/test/runtime/samples/svg-each-block-namespace/main.svelte
similarity index 100%
rename from test/runtime/samples/svg-each-block-namespace/main.html
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diff --git a/test/runtime/samples/transition-js-dynamic-component/A.html b/test/runtime/samples/transition-js-dynamic-component/A.svelte
similarity index 100%
rename from test/runtime/samples/transition-js-dynamic-component/A.html
rename to test/runtime/samples/transition-js-dynamic-component/A.svelte
diff --git a/test/runtime/samples/transition-js-dynamic-component/B.html b/test/runtime/samples/transition-js-dynamic-component/B.svelte
similarity index 100%
rename from test/runtime/samples/transition-js-dynamic-component/B.html
rename to test/runtime/samples/transition-js-dynamic-component/B.svelte
diff --git a/test/runtime/samples/transition-js-dynamic-component/main.html b/test/runtime/samples/transition-js-dynamic-component/main.html
deleted file mode 100644
index 85c88d9442..0000000000
--- a/test/runtime/samples/transition-js-dynamic-component/main.html
+++ /dev/null
@@ -1,8 +0,0 @@
-<script>
-	import A from './A.html';
-	import B from './B.html';
-
-	export let x;
-</script>
-
-<svelte:component this="{x ? A : B}"/>
\ No newline at end of file
diff --git a/test/runtime/samples/transition-js-dynamic-component/main.svelte b/test/runtime/samples/transition-js-dynamic-component/main.svelte
new file mode 100644
index 0000000000..08697ec1a9
--- /dev/null
+++ b/test/runtime/samples/transition-js-dynamic-component/main.svelte
@@ -0,0 +1,8 @@
+<script>
+	import A from './A.svelte';
+	import B from './B.svelte';
+
+	export let x;
+</script>
+
+<svelte:component this="{x ? A : B}"/>
\ No newline at end of file
diff --git a/test/runtime/samples/transition-js-dynamic-if-block-bidi/main.html b/test/runtime/samples/transition-js-dynamic-if-block-bidi/main.svelte
similarity index 100%
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similarity index 100%
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similarity index 100%
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similarity index 100%
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diff --git a/test/runtime/samples/transition-js-if-block-in-each-block-bidi-3/main.html b/test/runtime/samples/transition-js-if-block-in-each-block-bidi-3/main.svelte
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diff --git a/test/runtime/samples/transition-js-if-block-in-each-block-bidi/main.html b/test/runtime/samples/transition-js-if-block-in-each-block-bidi/main.svelte
similarity index 100%
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similarity index 100%
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diff --git a/test/runtime/samples/transition-js-if-else-block-dynamic-outro/main.html b/test/runtime/samples/transition-js-if-else-block-dynamic-outro/main.svelte
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diff --git a/test/runtime/samples/transition-js-intro-enabled-by-option/main.html b/test/runtime/samples/transition-js-intro-enabled-by-option/main.svelte
similarity index 100%
rename from test/runtime/samples/transition-js-intro-enabled-by-option/main.html
rename to test/runtime/samples/transition-js-intro-enabled-by-option/main.svelte
diff --git a/test/runtime/samples/transition-js-intro-skipped-by-default-nested/Widget.html b/test/runtime/samples/transition-js-intro-skipped-by-default-nested/Widget.svelte
similarity index 100%
rename from test/runtime/samples/transition-js-intro-skipped-by-default-nested/Widget.html
rename to test/runtime/samples/transition-js-intro-skipped-by-default-nested/Widget.svelte
diff --git a/test/runtime/samples/transition-js-intro-skipped-by-default-nested/main.html b/test/runtime/samples/transition-js-intro-skipped-by-default-nested/main.html
deleted file mode 100644
index cbcde3f1ed..0000000000
--- a/test/runtime/samples/transition-js-intro-skipped-by-default-nested/main.html
+++ /dev/null
@@ -1,5 +0,0 @@
-<script>
-	import Widget from './Widget.html';
-</script>
-
-<Widget/>
\ No newline at end of file
diff --git a/test/runtime/samples/transition-js-intro-skipped-by-default-nested/main.svelte b/test/runtime/samples/transition-js-intro-skipped-by-default-nested/main.svelte
new file mode 100644
index 0000000000..0a9d5bba87
--- /dev/null
+++ b/test/runtime/samples/transition-js-intro-skipped-by-default-nested/main.svelte
@@ -0,0 +1,5 @@
+<script>
+	import Widget from './Widget.svelte';
+</script>
+
+<Widget/>
\ No newline at end of file
diff --git a/test/runtime/samples/transition-js-intro-skipped-by-default/main.html b/test/runtime/samples/transition-js-intro-skipped-by-default/main.svelte
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diff --git a/test/runtime/samples/transition-js-local-nested-await/main.html b/test/runtime/samples/transition-js-local-nested-await/main.svelte
similarity index 100%
rename from test/runtime/samples/transition-js-local-nested-await/main.html
rename to test/runtime/samples/transition-js-local-nested-await/main.svelte
diff --git a/test/runtime/samples/transition-js-local-nested-component/Widget.html b/test/runtime/samples/transition-js-local-nested-component/Widget.svelte
similarity index 100%
rename from test/runtime/samples/transition-js-local-nested-component/Widget.html
rename to test/runtime/samples/transition-js-local-nested-component/Widget.svelte
diff --git a/test/runtime/samples/transition-js-local-nested-component/main.html b/test/runtime/samples/transition-js-local-nested-component/main.svelte
similarity index 55%
rename from test/runtime/samples/transition-js-local-nested-component/main.html
rename to test/runtime/samples/transition-js-local-nested-component/main.svelte
index 2eb867a667..761ef9d860 100644
--- a/test/runtime/samples/transition-js-local-nested-component/main.html
+++ b/test/runtime/samples/transition-js-local-nested-component/main.svelte
@@ -1,7 +1,7 @@
 <script>
 	export let x;
 
-	import Widget from './Widget.html';
+	import Widget from './Widget.svelte';
 </script>
 
 {#if x}
diff --git a/test/runtime/samples/transition-js-local-nested-each-keyed/main.html b/test/runtime/samples/transition-js-local-nested-each-keyed/main.svelte
similarity index 100%
rename from test/runtime/samples/transition-js-local-nested-each-keyed/main.html
rename to test/runtime/samples/transition-js-local-nested-each-keyed/main.svelte
diff --git a/test/runtime/samples/transition-js-local-nested-each/main.html b/test/runtime/samples/transition-js-local-nested-each/main.svelte
similarity index 100%
rename from test/runtime/samples/transition-js-local-nested-each/main.html
rename to test/runtime/samples/transition-js-local-nested-each/main.svelte
diff --git a/test/runtime/samples/transition-js-local-nested-if/main.html b/test/runtime/samples/transition-js-local-nested-if/main.svelte
similarity index 100%
rename from test/runtime/samples/transition-js-local-nested-if/main.html
rename to test/runtime/samples/transition-js-local-nested-if/main.svelte
diff --git a/test/runtime/samples/transition-js-local/main.html b/test/runtime/samples/transition-js-local/main.svelte
similarity index 100%
rename from test/runtime/samples/transition-js-local/main.html
rename to test/runtime/samples/transition-js-local/main.svelte
diff --git a/test/runtime/samples/transition-js-nested-await/main.html b/test/runtime/samples/transition-js-nested-await/main.svelte
similarity index 100%
rename from test/runtime/samples/transition-js-nested-await/main.html
rename to test/runtime/samples/transition-js-nested-await/main.svelte
diff --git a/test/runtime/samples/transition-js-nested-component/Widget.html b/test/runtime/samples/transition-js-nested-component/Widget.svelte
similarity index 100%
rename from test/runtime/samples/transition-js-nested-component/Widget.html
rename to test/runtime/samples/transition-js-nested-component/Widget.svelte
diff --git a/test/runtime/samples/transition-js-nested-component/main.html b/test/runtime/samples/transition-js-nested-component/main.svelte
similarity index 55%
rename from test/runtime/samples/transition-js-nested-component/main.html
rename to test/runtime/samples/transition-js-nested-component/main.svelte
index b4b3beccd8..8cfaa3bf02 100644
--- a/test/runtime/samples/transition-js-nested-component/main.html
+++ b/test/runtime/samples/transition-js-nested-component/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Widget from './Widget.html';
+	import Widget from './Widget.svelte';
 
 	export let x;
 </script>
diff --git a/test/runtime/samples/transition-js-nested-each-delete/main.html b/test/runtime/samples/transition-js-nested-each-delete/main.svelte
similarity index 100%
rename from test/runtime/samples/transition-js-nested-each-delete/main.html
rename to test/runtime/samples/transition-js-nested-each-delete/main.svelte
diff --git a/test/runtime/samples/transition-js-nested-each-keyed-2/Widget.html b/test/runtime/samples/transition-js-nested-each-keyed-2/Widget.svelte
similarity index 100%
rename from test/runtime/samples/transition-js-nested-each-keyed-2/Widget.html
rename to test/runtime/samples/transition-js-nested-each-keyed-2/Widget.svelte
diff --git a/test/runtime/samples/transition-js-nested-each-keyed-2/main.html b/test/runtime/samples/transition-js-nested-each-keyed-2/main.svelte
similarity index 65%
rename from test/runtime/samples/transition-js-nested-each-keyed-2/main.html
rename to test/runtime/samples/transition-js-nested-each-keyed-2/main.svelte
index 11096498cb..8a8ef57576 100644
--- a/test/runtime/samples/transition-js-nested-each-keyed-2/main.html
+++ b/test/runtime/samples/transition-js-nested-each-keyed-2/main.svelte
@@ -2,7 +2,7 @@
 	export let x;
 	export let things;
 
-	import Widget from './Widget.html';
+	import Widget from './Widget.svelte';
 </script>
 
 {#if x}
diff --git a/test/runtime/samples/transition-js-nested-each-keyed/main.html b/test/runtime/samples/transition-js-nested-each-keyed/main.svelte
similarity index 100%
rename from test/runtime/samples/transition-js-nested-each-keyed/main.html
rename to test/runtime/samples/transition-js-nested-each-keyed/main.svelte
diff --git a/test/runtime/samples/transition-js-nested-each/main.html b/test/runtime/samples/transition-js-nested-each/main.svelte
similarity index 100%
rename from test/runtime/samples/transition-js-nested-each/main.html
rename to test/runtime/samples/transition-js-nested-each/main.svelte
diff --git a/test/runtime/samples/transition-js-nested-if/main.html b/test/runtime/samples/transition-js-nested-if/main.svelte
similarity index 100%
rename from test/runtime/samples/transition-js-nested-if/main.html
rename to test/runtime/samples/transition-js-nested-if/main.svelte
diff --git a/test/runtime/samples/transition-js-nested-intro/Child.html b/test/runtime/samples/transition-js-nested-intro/Child.svelte
similarity index 100%
rename from test/runtime/samples/transition-js-nested-intro/Child.html
rename to test/runtime/samples/transition-js-nested-intro/Child.svelte
diff --git a/test/runtime/samples/transition-js-nested-intro/main.html b/test/runtime/samples/transition-js-nested-intro/main.svelte
similarity index 65%
rename from test/runtime/samples/transition-js-nested-intro/main.html
rename to test/runtime/samples/transition-js-nested-intro/main.svelte
index f222940ad5..5ae29bee7b 100644
--- a/test/runtime/samples/transition-js-nested-intro/main.html
+++ b/test/runtime/samples/transition-js-nested-intro/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Child from './Child.html';
+	import Child from './Child.svelte';
 	export let visible;
 </script>
 
diff --git a/test/runtime/samples/transition-js-parameterised-with-state/main.html b/test/runtime/samples/transition-js-parameterised-with-state/main.svelte
similarity index 100%
rename from test/runtime/samples/transition-js-parameterised-with-state/main.html
rename to test/runtime/samples/transition-js-parameterised-with-state/main.svelte
diff --git a/test/runtime/samples/transition-js-parameterised/main.html b/test/runtime/samples/transition-js-parameterised/main.svelte
similarity index 100%
rename from test/runtime/samples/transition-js-parameterised/main.html
rename to test/runtime/samples/transition-js-parameterised/main.svelte
diff --git a/test/runtime/samples/whitespace-each-block/main.html b/test/runtime/samples/whitespace-each-block/main.svelte
similarity index 100%
rename from test/runtime/samples/whitespace-each-block/main.html
rename to test/runtime/samples/whitespace-each-block/main.svelte
diff --git a/test/runtime/samples/whitespace-list/main.html b/test/runtime/samples/whitespace-list/main.svelte
similarity index 100%
rename from test/runtime/samples/whitespace-list/main.html
rename to test/runtime/samples/whitespace-list/main.svelte
diff --git a/test/runtime/samples/whitespace-normal/main.html b/test/runtime/samples/whitespace-normal/main.svelte
similarity index 100%
rename from test/runtime/samples/whitespace-normal/main.html
rename to test/runtime/samples/whitespace-normal/main.svelte
diff --git a/test/runtime/samples/window-bind-scroll-update/main.html b/test/runtime/samples/window-bind-scroll-update/main.svelte
similarity index 100%
rename from test/runtime/samples/window-bind-scroll-update/main.html
rename to test/runtime/samples/window-bind-scroll-update/main.svelte
diff --git a/test/runtime/samples/window-binding-multiple-handlers/main.html b/test/runtime/samples/window-binding-multiple-handlers/main.svelte
similarity index 100%
rename from test/runtime/samples/window-binding-multiple-handlers/main.html
rename to test/runtime/samples/window-binding-multiple-handlers/main.svelte
diff --git a/test/runtime/samples/window-binding-resize/main.html b/test/runtime/samples/window-binding-resize/main.svelte
similarity index 100%
rename from test/runtime/samples/window-binding-resize/main.html
rename to test/runtime/samples/window-binding-resize/main.svelte
diff --git a/test/runtime/samples/window-event-context/main.html b/test/runtime/samples/window-event-context/main.svelte
similarity index 100%
rename from test/runtime/samples/window-event-context/main.html
rename to test/runtime/samples/window-event-context/main.svelte
diff --git a/test/runtime/samples/window-event-custom/main.html b/test/runtime/samples/window-event-custom/main.svelte
similarity index 100%
rename from test/runtime/samples/window-event-custom/main.html
rename to test/runtime/samples/window-event-custom/main.svelte
diff --git a/test/runtime/samples/window-event/main.html b/test/runtime/samples/window-event/main.svelte
similarity index 100%
rename from test/runtime/samples/window-event/main.html
rename to test/runtime/samples/window-event/main.svelte
diff --git a/test/server-side-rendering/samples/attribute-boolean/_expected.html b/test/server-side-rendering/samples/attribute-boolean/_expected.svelte
similarity index 100%
rename from test/server-side-rendering/samples/attribute-boolean/_expected.html
rename to test/server-side-rendering/samples/attribute-boolean/_expected.svelte
diff --git a/test/server-side-rendering/samples/attribute-boolean/main.html b/test/server-side-rendering/samples/attribute-boolean/main.svelte
similarity index 100%
rename from test/server-side-rendering/samples/attribute-boolean/main.html
rename to test/server-side-rendering/samples/attribute-boolean/main.svelte
diff --git a/test/server-side-rendering/samples/attribute-dynamic/_expected.html b/test/server-side-rendering/samples/attribute-dynamic/_expected.svelte
similarity index 100%
rename from test/server-side-rendering/samples/attribute-dynamic/_expected.html
rename to test/server-side-rendering/samples/attribute-dynamic/_expected.svelte
diff --git a/test/server-side-rendering/samples/attribute-dynamic/main.html b/test/server-side-rendering/samples/attribute-dynamic/main.svelte
similarity index 100%
rename from test/server-side-rendering/samples/attribute-dynamic/main.html
rename to test/server-side-rendering/samples/attribute-dynamic/main.svelte
diff --git a/test/server-side-rendering/samples/attribute-escaped-quotes-spread/_expected.html b/test/server-side-rendering/samples/attribute-escaped-quotes-spread/_expected.svelte
similarity index 100%
rename from test/server-side-rendering/samples/attribute-escaped-quotes-spread/_expected.html
rename to test/server-side-rendering/samples/attribute-escaped-quotes-spread/_expected.svelte
diff --git a/test/server-side-rendering/samples/attribute-escaped-quotes-spread/main.html b/test/server-side-rendering/samples/attribute-escaped-quotes-spread/main.svelte
similarity index 100%
rename from test/server-side-rendering/samples/attribute-escaped-quotes-spread/main.html
rename to test/server-side-rendering/samples/attribute-escaped-quotes-spread/main.svelte
diff --git a/test/server-side-rendering/samples/attribute-escaped-quotes/_expected.html b/test/server-side-rendering/samples/attribute-escaped-quotes/_expected.svelte
similarity index 100%
rename from test/server-side-rendering/samples/attribute-escaped-quotes/_expected.html
rename to test/server-side-rendering/samples/attribute-escaped-quotes/_expected.svelte
diff --git a/test/server-side-rendering/samples/attribute-escaped-quotes/main.html b/test/server-side-rendering/samples/attribute-escaped-quotes/main.svelte
similarity index 100%
rename from test/server-side-rendering/samples/attribute-escaped-quotes/main.html
rename to test/server-side-rendering/samples/attribute-escaped-quotes/main.svelte
diff --git a/test/server-side-rendering/samples/attribute-static/_expected.html b/test/server-side-rendering/samples/attribute-static/_expected.svelte
similarity index 100%
rename from test/server-side-rendering/samples/attribute-static/_expected.html
rename to test/server-side-rendering/samples/attribute-static/_expected.svelte
diff --git a/test/server-side-rendering/samples/attribute-static/main.html b/test/server-side-rendering/samples/attribute-static/main.svelte
similarity index 100%
rename from test/server-side-rendering/samples/attribute-static/main.html
rename to test/server-side-rendering/samples/attribute-static/main.svelte
diff --git a/test/server-side-rendering/samples/bindings/_expected.html b/test/server-side-rendering/samples/bindings/_expected.svelte
similarity index 100%
rename from test/server-side-rendering/samples/bindings/_expected.html
rename to test/server-side-rendering/samples/bindings/_expected.svelte
diff --git a/test/server-side-rendering/samples/bindings/main.html b/test/server-side-rendering/samples/bindings/main.svelte
similarity index 100%
rename from test/server-side-rendering/samples/bindings/main.html
rename to test/server-side-rendering/samples/bindings/main.svelte
diff --git a/test/server-side-rendering/samples/comment/_expected.html b/test/server-side-rendering/samples/comment/_expected.svelte
similarity index 100%
rename from test/server-side-rendering/samples/comment/_expected.html
rename to test/server-side-rendering/samples/comment/_expected.svelte
diff --git a/test/server-side-rendering/samples/comment/main.html b/test/server-side-rendering/samples/comment/main.svelte
similarity index 100%
rename from test/server-side-rendering/samples/comment/main.html
rename to test/server-side-rendering/samples/comment/main.svelte
diff --git a/test/server-side-rendering/samples/component-binding-renamed/Foo.html b/test/server-side-rendering/samples/component-binding-renamed/Foo.svelte
similarity index 100%
rename from test/server-side-rendering/samples/component-binding-renamed/Foo.html
rename to test/server-side-rendering/samples/component-binding-renamed/Foo.svelte
diff --git a/test/server-side-rendering/samples/component-binding-renamed/_expected.html b/test/server-side-rendering/samples/component-binding-renamed/_expected.svelte
similarity index 100%
rename from test/server-side-rendering/samples/component-binding-renamed/_expected.html
rename to test/server-side-rendering/samples/component-binding-renamed/_expected.svelte
diff --git a/test/server-side-rendering/samples/component-binding-renamed/main.html b/test/server-side-rendering/samples/component-binding-renamed/main.svelte
similarity index 69%
rename from test/server-side-rendering/samples/component-binding-renamed/main.html
rename to test/server-side-rendering/samples/component-binding-renamed/main.svelte
index 5c8af5f2ea..927239e1ec 100644
--- a/test/server-side-rendering/samples/component-binding-renamed/main.html
+++ b/test/server-side-rendering/samples/component-binding-renamed/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Foo from './Foo.html';
+	import Foo from './Foo.svelte';
 
 	export let x;
 	export let y;
diff --git a/test/server-side-rendering/samples/component-binding/Foo.html b/test/server-side-rendering/samples/component-binding/Foo.svelte
similarity index 100%
rename from test/server-side-rendering/samples/component-binding/Foo.html
rename to test/server-side-rendering/samples/component-binding/Foo.svelte
diff --git a/test/server-side-rendering/samples/component-binding/_expected.html b/test/server-side-rendering/samples/component-binding/_expected.svelte
similarity index 100%
rename from test/server-side-rendering/samples/component-binding/_expected.html
rename to test/server-side-rendering/samples/component-binding/_expected.svelte
diff --git a/test/server-side-rendering/samples/component-binding/main.html b/test/server-side-rendering/samples/component-binding/main.svelte
similarity index 62%
rename from test/server-side-rendering/samples/component-binding/main.html
rename to test/server-side-rendering/samples/component-binding/main.svelte
index c8742a5843..c7f2d56566 100644
--- a/test/server-side-rendering/samples/component-binding/main.html
+++ b/test/server-side-rendering/samples/component-binding/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Foo from './Foo.html';
+	import Foo from './Foo.svelte';
 
 	export let x;
 </script>
diff --git a/test/server-side-rendering/samples/component-data-dynamic/Widget.html b/test/server-side-rendering/samples/component-data-dynamic/Widget.svelte
similarity index 100%
rename from test/server-side-rendering/samples/component-data-dynamic/Widget.html
rename to test/server-side-rendering/samples/component-data-dynamic/Widget.svelte
diff --git a/test/server-side-rendering/samples/component-data-dynamic/_expected.html b/test/server-side-rendering/samples/component-data-dynamic/_expected.svelte
similarity index 100%
rename from test/server-side-rendering/samples/component-data-dynamic/_expected.html
rename to test/server-side-rendering/samples/component-data-dynamic/_expected.svelte
diff --git a/test/server-side-rendering/samples/component-data-dynamic/main.html b/test/server-side-rendering/samples/component-data-dynamic/main.svelte
similarity index 83%
rename from test/server-side-rendering/samples/component-data-dynamic/main.html
rename to test/server-side-rendering/samples/component-data-dynamic/main.svelte
index 74998f4742..ce7f22d6ea 100644
--- a/test/server-side-rendering/samples/component-data-dynamic/main.html
+++ b/test/server-side-rendering/samples/component-data-dynamic/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Widget from './Widget.html';
+	import Widget from './Widget.svelte';
 
 	export let bar;
 	export let x;
diff --git a/test/server-side-rendering/samples/component-data-empty/Widget.html b/test/server-side-rendering/samples/component-data-empty/Widget.svelte
similarity index 100%
rename from test/server-side-rendering/samples/component-data-empty/Widget.html
rename to test/server-side-rendering/samples/component-data-empty/Widget.svelte
diff --git a/test/server-side-rendering/samples/component-data-empty/_expected.html b/test/server-side-rendering/samples/component-data-empty/_expected.svelte
similarity index 100%
rename from test/server-side-rendering/samples/component-data-empty/_expected.html
rename to test/server-side-rendering/samples/component-data-empty/_expected.svelte
diff --git a/test/server-side-rendering/samples/component-data-empty/main.html b/test/server-side-rendering/samples/component-data-empty/main.svelte
similarity index 56%
rename from test/server-side-rendering/samples/component-data-empty/main.html
rename to test/server-side-rendering/samples/component-data-empty/main.svelte
index 478bcff0a1..472429d7f6 100644
--- a/test/server-side-rendering/samples/component-data-empty/main.html
+++ b/test/server-side-rendering/samples/component-data-empty/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Widget from './Widget.html';
+	import Widget from './Widget.svelte';
 </script>
 
 <div>
diff --git a/test/server-side-rendering/samples/component-refs-and-attributes/Widget.html b/test/server-side-rendering/samples/component-refs-and-attributes/Widget.svelte
similarity index 100%
rename from test/server-side-rendering/samples/component-refs-and-attributes/Widget.html
rename to test/server-side-rendering/samples/component-refs-and-attributes/Widget.svelte
diff --git a/test/server-side-rendering/samples/component-refs-and-attributes/_expected.html b/test/server-side-rendering/samples/component-refs-and-attributes/_expected.svelte
similarity index 100%
rename from test/server-side-rendering/samples/component-refs-and-attributes/_expected.html
rename to test/server-side-rendering/samples/component-refs-and-attributes/_expected.svelte
diff --git a/test/server-side-rendering/samples/component-refs-and-attributes/main.html b/test/server-side-rendering/samples/component-refs-and-attributes/main.svelte
similarity index 74%
rename from test/server-side-rendering/samples/component-refs-and-attributes/main.html
rename to test/server-side-rendering/samples/component-refs-and-attributes/main.svelte
index 8192bdf402..5c86521df5 100644
--- a/test/server-side-rendering/samples/component-refs-and-attributes/main.html
+++ b/test/server-side-rendering/samples/component-refs-and-attributes/main.svelte
@@ -1,7 +1,7 @@
 <script>
 	export let widget;
 
-	import Widget from './Widget.html';
+	import Widget from './Widget.svelte';
 
 	export let foo = 42;
 </script>
diff --git a/test/server-side-rendering/samples/component-refs/Widget.html b/test/server-side-rendering/samples/component-refs/Widget.svelte
similarity index 100%
rename from test/server-side-rendering/samples/component-refs/Widget.html
rename to test/server-side-rendering/samples/component-refs/Widget.svelte
diff --git a/test/server-side-rendering/samples/component-refs/_expected.html b/test/server-side-rendering/samples/component-refs/_expected.svelte
similarity index 100%
rename from test/server-side-rendering/samples/component-refs/_expected.html
rename to test/server-side-rendering/samples/component-refs/_expected.svelte
diff --git a/test/server-side-rendering/samples/component-refs/main.html b/test/server-side-rendering/samples/component-refs/main.svelte
similarity index 67%
rename from test/server-side-rendering/samples/component-refs/main.html
rename to test/server-side-rendering/samples/component-refs/main.svelte
index 96b3d15de4..6ec0bc5438 100644
--- a/test/server-side-rendering/samples/component-refs/main.html
+++ b/test/server-side-rendering/samples/component-refs/main.svelte
@@ -1,7 +1,7 @@
 <script>
 	export let widget;
 
-	import Widget from './Widget.html';
+	import Widget from './Widget.svelte';
 </script>
 
 <div><Widget bind:this={widget}/></div>
diff --git a/test/server-side-rendering/samples/component-with-different-extension/_expected.html b/test/server-side-rendering/samples/component-with-different-extension/_expected.svelte
similarity index 100%
rename from test/server-side-rendering/samples/component-with-different-extension/_expected.html
rename to test/server-side-rendering/samples/component-with-different-extension/_expected.svelte
diff --git a/test/server-side-rendering/samples/component-yield/Widget.html b/test/server-side-rendering/samples/component-yield/Widget.svelte
similarity index 100%
rename from test/server-side-rendering/samples/component-yield/Widget.html
rename to test/server-side-rendering/samples/component-yield/Widget.svelte
diff --git a/test/server-side-rendering/samples/component-yield/_expected.html b/test/server-side-rendering/samples/component-yield/_expected.svelte
similarity index 100%
rename from test/server-side-rendering/samples/component-yield/_expected.html
rename to test/server-side-rendering/samples/component-yield/_expected.svelte
diff --git a/test/server-side-rendering/samples/component-yield/main.html b/test/server-side-rendering/samples/component-yield/main.svelte
similarity index 69%
rename from test/server-side-rendering/samples/component-yield/main.html
rename to test/server-side-rendering/samples/component-yield/main.svelte
index 9c2f573c91..2dbd669a78 100644
--- a/test/server-side-rendering/samples/component-yield/main.html
+++ b/test/server-side-rendering/samples/component-yield/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Widget from './Widget.html';
+	import Widget from './Widget.svelte';
 
 	export let data = 'Hello';
 </script>
diff --git a/test/server-side-rendering/samples/component/Widget.html b/test/server-side-rendering/samples/component/Widget.svelte
similarity index 100%
rename from test/server-side-rendering/samples/component/Widget.html
rename to test/server-side-rendering/samples/component/Widget.svelte
diff --git a/test/server-side-rendering/samples/component/_expected.html b/test/server-side-rendering/samples/component/_expected.svelte
similarity index 100%
rename from test/server-side-rendering/samples/component/_expected.html
rename to test/server-side-rendering/samples/component/_expected.svelte
diff --git a/test/server-side-rendering/samples/component/main.html b/test/server-side-rendering/samples/component/main.svelte
similarity index 53%
rename from test/server-side-rendering/samples/component/main.html
rename to test/server-side-rendering/samples/component/main.svelte
index ecb4297a40..ac0b429163 100644
--- a/test/server-side-rendering/samples/component/main.html
+++ b/test/server-side-rendering/samples/component/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Widget from './Widget.html';
+	import Widget from './Widget.svelte';
 </script>
 
 <div>
diff --git a/test/server-side-rendering/samples/computed/_expected.html b/test/server-side-rendering/samples/computed/_expected.svelte
similarity index 100%
rename from test/server-side-rendering/samples/computed/_expected.html
rename to test/server-side-rendering/samples/computed/_expected.svelte
diff --git a/test/server-side-rendering/samples/computed/main.html b/test/server-side-rendering/samples/computed/main.svelte
similarity index 100%
rename from test/server-side-rendering/samples/computed/main.html
rename to test/server-side-rendering/samples/computed/main.svelte
diff --git a/test/server-side-rendering/samples/default-data-override/_expected.html b/test/server-side-rendering/samples/default-data-override/_expected.svelte
similarity index 100%
rename from test/server-side-rendering/samples/default-data-override/_expected.html
rename to test/server-side-rendering/samples/default-data-override/_expected.svelte
diff --git a/test/server-side-rendering/samples/default-data-override/main.html b/test/server-side-rendering/samples/default-data-override/main.svelte
similarity index 100%
rename from test/server-side-rendering/samples/default-data-override/main.html
rename to test/server-side-rendering/samples/default-data-override/main.svelte
diff --git a/test/server-side-rendering/samples/default-data/_expected.html b/test/server-side-rendering/samples/default-data/_expected.svelte
similarity index 100%
rename from test/server-side-rendering/samples/default-data/_expected.html
rename to test/server-side-rendering/samples/default-data/_expected.svelte
diff --git a/test/server-side-rendering/samples/default-data/main.html b/test/server-side-rendering/samples/default-data/main.svelte
similarity index 100%
rename from test/server-side-rendering/samples/default-data/main.html
rename to test/server-side-rendering/samples/default-data/main.svelte
diff --git a/test/server-side-rendering/samples/directives/_expected.html b/test/server-side-rendering/samples/directives/_expected.svelte
similarity index 100%
rename from test/server-side-rendering/samples/directives/_expected.html
rename to test/server-side-rendering/samples/directives/_expected.svelte
diff --git a/test/server-side-rendering/samples/directives/main.html b/test/server-side-rendering/samples/directives/main.svelte
similarity index 100%
rename from test/server-side-rendering/samples/directives/main.html
rename to test/server-side-rendering/samples/directives/main.svelte
diff --git a/test/server-side-rendering/samples/dynamic-text-escaped/_expected.html b/test/server-side-rendering/samples/dynamic-text-escaped/_expected.svelte
similarity index 100%
rename from test/server-side-rendering/samples/dynamic-text-escaped/_expected.html
rename to test/server-side-rendering/samples/dynamic-text-escaped/_expected.svelte
diff --git a/test/server-side-rendering/samples/dynamic-text-escaped/main.html b/test/server-side-rendering/samples/dynamic-text-escaped/main.svelte
similarity index 100%
rename from test/server-side-rendering/samples/dynamic-text-escaped/main.html
rename to test/server-side-rendering/samples/dynamic-text-escaped/main.svelte
diff --git a/test/server-side-rendering/samples/dynamic-text/_expected.html b/test/server-side-rendering/samples/dynamic-text/_expected.svelte
similarity index 100%
rename from test/server-side-rendering/samples/dynamic-text/_expected.html
rename to test/server-side-rendering/samples/dynamic-text/_expected.svelte
diff --git a/test/server-side-rendering/samples/dynamic-text/main.html b/test/server-side-rendering/samples/dynamic-text/main.svelte
similarity index 100%
rename from test/server-side-rendering/samples/dynamic-text/main.html
rename to test/server-side-rendering/samples/dynamic-text/main.svelte
diff --git a/test/server-side-rendering/samples/each-block/_expected.html b/test/server-side-rendering/samples/each-block/_expected.svelte
similarity index 100%
rename from test/server-side-rendering/samples/each-block/_expected.html
rename to test/server-side-rendering/samples/each-block/_expected.svelte
diff --git a/test/server-side-rendering/samples/each-block/main.html b/test/server-side-rendering/samples/each-block/main.svelte
similarity index 100%
rename from test/server-side-rendering/samples/each-block/main.html
rename to test/server-side-rendering/samples/each-block/main.svelte
diff --git a/test/server-side-rendering/samples/empty-elements-closed/_expected.html b/test/server-side-rendering/samples/empty-elements-closed/_expected.svelte
similarity index 100%
rename from test/server-side-rendering/samples/empty-elements-closed/_expected.html
rename to test/server-side-rendering/samples/empty-elements-closed/_expected.svelte
diff --git a/test/server-side-rendering/samples/empty-elements-closed/main.html b/test/server-side-rendering/samples/empty-elements-closed/main.svelte
similarity index 100%
rename from test/server-side-rendering/samples/empty-elements-closed/main.html
rename to test/server-side-rendering/samples/empty-elements-closed/main.svelte
diff --git a/test/server-side-rendering/samples/entities/_expected.html b/test/server-side-rendering/samples/entities/_expected.svelte
similarity index 100%
rename from test/server-side-rendering/samples/entities/_expected.html
rename to test/server-side-rendering/samples/entities/_expected.svelte
diff --git a/test/server-side-rendering/samples/entities/main.html b/test/server-side-rendering/samples/entities/main.svelte
similarity index 100%
rename from test/server-side-rendering/samples/entities/main.html
rename to test/server-side-rendering/samples/entities/main.svelte
diff --git a/test/server-side-rendering/samples/head-title/_expected-head.html b/test/server-side-rendering/samples/head-title/_expected-head.html
deleted file mode 100644
index 7d696352f9..0000000000
--- a/test/server-side-rendering/samples/head-title/_expected-head.html
+++ /dev/null
@@ -1 +0,0 @@
-<title>a custom title</title>
\ No newline at end of file
diff --git a/test/server-side-rendering/samples/head-title/_actual-head.html b/test/server-side-rendering/samples/head-title/_expected-head.svelte
similarity index 100%
rename from test/server-side-rendering/samples/head-title/_actual-head.html
rename to test/server-side-rendering/samples/head-title/_expected-head.svelte
diff --git a/test/server-side-rendering/samples/head-title/_expected.html b/test/server-side-rendering/samples/head-title/_expected.svelte
similarity index 100%
rename from test/server-side-rendering/samples/head-title/_expected.html
rename to test/server-side-rendering/samples/head-title/_expected.svelte
diff --git a/test/server-side-rendering/samples/head-title/main.html b/test/server-side-rendering/samples/head-title/main.svelte
similarity index 100%
rename from test/server-side-rendering/samples/head-title/main.html
rename to test/server-side-rendering/samples/head-title/main.svelte
diff --git a/test/server-side-rendering/samples/helpers/_expected.html b/test/server-side-rendering/samples/helpers/_expected.svelte
similarity index 100%
rename from test/server-side-rendering/samples/helpers/_expected.html
rename to test/server-side-rendering/samples/helpers/_expected.svelte
diff --git a/test/server-side-rendering/samples/helpers/main.html b/test/server-side-rendering/samples/helpers/main.svelte
similarity index 100%
rename from test/server-side-rendering/samples/helpers/main.html
rename to test/server-side-rendering/samples/helpers/main.svelte
diff --git a/test/server-side-rendering/samples/if-block-false/_expected.html b/test/server-side-rendering/samples/if-block-false/_expected.svelte
similarity index 100%
rename from test/server-side-rendering/samples/if-block-false/_expected.html
rename to test/server-side-rendering/samples/if-block-false/_expected.svelte
diff --git a/test/server-side-rendering/samples/if-block-false/main.html b/test/server-side-rendering/samples/if-block-false/main.svelte
similarity index 100%
rename from test/server-side-rendering/samples/if-block-false/main.html
rename to test/server-side-rendering/samples/if-block-false/main.svelte
diff --git a/test/server-side-rendering/samples/if-block-true/_expected.html b/test/server-side-rendering/samples/if-block-true/_expected.svelte
similarity index 100%
rename from test/server-side-rendering/samples/if-block-true/_expected.html
rename to test/server-side-rendering/samples/if-block-true/_expected.svelte
diff --git a/test/server-side-rendering/samples/if-block-true/main.html b/test/server-side-rendering/samples/if-block-true/main.svelte
similarity index 100%
rename from test/server-side-rendering/samples/if-block-true/main.html
rename to test/server-side-rendering/samples/if-block-true/main.svelte
diff --git a/test/server-side-rendering/samples/import-non-component/_expected.html b/test/server-side-rendering/samples/import-non-component/_expected.svelte
similarity index 100%
rename from test/server-side-rendering/samples/import-non-component/_expected.html
rename to test/server-side-rendering/samples/import-non-component/_expected.svelte
diff --git a/test/server-side-rendering/samples/import-non-component/main.html b/test/server-side-rendering/samples/import-non-component/main.svelte
similarity index 100%
rename from test/server-side-rendering/samples/import-non-component/main.html
rename to test/server-side-rendering/samples/import-non-component/main.svelte
diff --git a/test/server-side-rendering/samples/raw-mustaches/_expected.html b/test/server-side-rendering/samples/raw-mustaches/_expected.svelte
similarity index 100%
rename from test/server-side-rendering/samples/raw-mustaches/_expected.html
rename to test/server-side-rendering/samples/raw-mustaches/_expected.svelte
diff --git a/test/server-side-rendering/samples/raw-mustaches/main.html b/test/server-side-rendering/samples/raw-mustaches/main.svelte
similarity index 100%
rename from test/server-side-rendering/samples/raw-mustaches/main.html
rename to test/server-side-rendering/samples/raw-mustaches/main.svelte
diff --git a/test/server-side-rendering/samples/sanitize-name/[foo].html b/test/server-side-rendering/samples/sanitize-name/[foo].svelte
similarity index 100%
rename from test/server-side-rendering/samples/sanitize-name/[foo].html
rename to test/server-side-rendering/samples/sanitize-name/[foo].svelte
diff --git a/test/server-side-rendering/samples/sanitize-name/_expected.html b/test/server-side-rendering/samples/sanitize-name/_expected.svelte
similarity index 100%
rename from test/server-side-rendering/samples/sanitize-name/_expected.html
rename to test/server-side-rendering/samples/sanitize-name/_expected.svelte
diff --git a/test/server-side-rendering/samples/sanitize-name/main.html b/test/server-side-rendering/samples/sanitize-name/main.html
deleted file mode 100644
index 6d7986da2e..0000000000
--- a/test/server-side-rendering/samples/sanitize-name/main.html
+++ /dev/null
@@ -1,5 +0,0 @@
-<script>
-	import Foo from './[foo].html';
-</script>
-
-<Foo/>
\ No newline at end of file
diff --git a/test/server-side-rendering/samples/sanitize-name/main.svelte b/test/server-side-rendering/samples/sanitize-name/main.svelte
new file mode 100644
index 0000000000..1438843da9
--- /dev/null
+++ b/test/server-side-rendering/samples/sanitize-name/main.svelte
@@ -0,0 +1,5 @@
+<script>
+	import Foo from './[foo].svelte';
+</script>
+
+<Foo/>
\ No newline at end of file
diff --git a/test/server-side-rendering/samples/static-div/_expected.html b/test/server-side-rendering/samples/static-div/_expected.svelte
similarity index 100%
rename from test/server-side-rendering/samples/static-div/_expected.html
rename to test/server-side-rendering/samples/static-div/_expected.svelte
diff --git a/test/server-side-rendering/samples/static-div/main.html b/test/server-side-rendering/samples/static-div/main.svelte
similarity index 100%
rename from test/server-side-rendering/samples/static-div/main.html
rename to test/server-side-rendering/samples/static-div/main.svelte
diff --git a/test/server-side-rendering/samples/static-text/_expected.html b/test/server-side-rendering/samples/static-text/_expected.svelte
similarity index 100%
rename from test/server-side-rendering/samples/static-text/_expected.html
rename to test/server-side-rendering/samples/static-text/_expected.svelte
diff --git a/test/server-side-rendering/samples/static-text/main.html b/test/server-side-rendering/samples/static-text/main.svelte
similarity index 100%
rename from test/server-side-rendering/samples/static-text/main.html
rename to test/server-side-rendering/samples/static-text/main.svelte
diff --git a/test/server-side-rendering/samples/styles-nested/One.html b/test/server-side-rendering/samples/styles-nested/One.svelte
similarity index 84%
rename from test/server-side-rendering/samples/styles-nested/One.html
rename to test/server-side-rendering/samples/styles-nested/One.svelte
index df5512b91a..94b44675c8 100644
--- a/test/server-side-rendering/samples/styles-nested/One.html
+++ b/test/server-side-rendering/samples/styles-nested/One.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Two from './Two.html';
+	import Two from './Two.svelte';
 
 	export let message;
 </script>
diff --git a/test/server-side-rendering/samples/styles-nested/Two.html b/test/server-side-rendering/samples/styles-nested/Two.svelte
similarity index 100%
rename from test/server-side-rendering/samples/styles-nested/Two.html
rename to test/server-side-rendering/samples/styles-nested/Two.svelte
diff --git a/test/server-side-rendering/samples/styles-nested/_expected.html b/test/server-side-rendering/samples/styles-nested/_expected.svelte
similarity index 100%
rename from test/server-side-rendering/samples/styles-nested/_expected.html
rename to test/server-side-rendering/samples/styles-nested/_expected.svelte
diff --git a/test/server-side-rendering/samples/styles-nested/main.html b/test/server-side-rendering/samples/styles-nested/main.svelte
similarity index 78%
rename from test/server-side-rendering/samples/styles-nested/main.html
rename to test/server-side-rendering/samples/styles-nested/main.svelte
index 11775475b8..d6f1d594e3 100644
--- a/test/server-side-rendering/samples/styles-nested/main.html
+++ b/test/server-side-rendering/samples/styles-nested/main.svelte
@@ -1,5 +1,5 @@
 <script>
-	import One from './One.html';
+	import One from './One.svelte';
 </script>
 
 <div>red</div>
diff --git a/test/server-side-rendering/samples/styles/_expected.html b/test/server-side-rendering/samples/styles/_expected.svelte
similarity index 100%
rename from test/server-side-rendering/samples/styles/_expected.html
rename to test/server-side-rendering/samples/styles/_expected.svelte
diff --git a/test/server-side-rendering/samples/styles/main.html b/test/server-side-rendering/samples/styles/main.svelte
similarity index 100%
rename from test/server-side-rendering/samples/styles/main.html
rename to test/server-side-rendering/samples/styles/main.svelte
diff --git a/test/server-side-rendering/samples/textarea-children/_expected.html b/test/server-side-rendering/samples/textarea-children/_expected.svelte
similarity index 100%
rename from test/server-side-rendering/samples/textarea-children/_expected.html
rename to test/server-side-rendering/samples/textarea-children/_expected.svelte
diff --git a/test/server-side-rendering/samples/textarea-children/main.html b/test/server-side-rendering/samples/textarea-children/main.svelte
similarity index 100%
rename from test/server-side-rendering/samples/textarea-children/main.html
rename to test/server-side-rendering/samples/textarea-children/main.svelte
diff --git a/test/server-side-rendering/samples/textarea-value/_expected.html b/test/server-side-rendering/samples/textarea-value/_expected.svelte
similarity index 100%
rename from test/server-side-rendering/samples/textarea-value/_expected.html
rename to test/server-side-rendering/samples/textarea-value/_expected.svelte
diff --git a/test/server-side-rendering/samples/textarea-value/main.html b/test/server-side-rendering/samples/textarea-value/main.svelte
similarity index 100%
rename from test/server-side-rendering/samples/textarea-value/main.html
rename to test/server-side-rendering/samples/textarea-value/main.svelte
diff --git a/test/server-side-rendering/samples/triple/_expected.html b/test/server-side-rendering/samples/triple/_expected.svelte
similarity index 100%
rename from test/server-side-rendering/samples/triple/_expected.html
rename to test/server-side-rendering/samples/triple/_expected.svelte
diff --git a/test/server-side-rendering/samples/triple/main.html b/test/server-side-rendering/samples/triple/main.svelte
similarity index 100%
rename from test/server-side-rendering/samples/triple/main.html
rename to test/server-side-rendering/samples/triple/main.svelte
diff --git a/test/sourcemaps/samples/basic/input.html b/test/sourcemaps/samples/basic/input.svelte
similarity index 100%
rename from test/sourcemaps/samples/basic/input.html
rename to test/sourcemaps/samples/basic/input.svelte
diff --git a/test/sourcemaps/samples/binding-shorthand.skip/input.html b/test/sourcemaps/samples/binding-shorthand.skip/input.svelte
similarity index 100%
rename from test/sourcemaps/samples/binding-shorthand.skip/input.html
rename to test/sourcemaps/samples/binding-shorthand.skip/input.svelte
diff --git a/test/sourcemaps/samples/binding/input.html b/test/sourcemaps/samples/binding/input.svelte
similarity index 100%
rename from test/sourcemaps/samples/binding/input.html
rename to test/sourcemaps/samples/binding/input.svelte
diff --git a/test/sourcemaps/samples/css/input.html b/test/sourcemaps/samples/css/input.svelte
similarity index 100%
rename from test/sourcemaps/samples/css/input.html
rename to test/sourcemaps/samples/css/input.svelte
diff --git a/test/sourcemaps/samples/each-block/input.html b/test/sourcemaps/samples/each-block/input.svelte
similarity index 100%
rename from test/sourcemaps/samples/each-block/input.html
rename to test/sourcemaps/samples/each-block/input.svelte
diff --git a/test/sourcemaps/samples/script/input.html b/test/sourcemaps/samples/script/input.svelte
similarity index 100%
rename from test/sourcemaps/samples/script/input.html
rename to test/sourcemaps/samples/script/input.svelte
diff --git a/test/sourcemaps/samples/static-no-script/input.html b/test/sourcemaps/samples/static-no-script/input.svelte
similarity index 100%
rename from test/sourcemaps/samples/static-no-script/input.html
rename to test/sourcemaps/samples/static-no-script/input.svelte
diff --git a/test/stats/samples/basic/input.html b/test/stats/samples/basic/input.svelte
similarity index 100%
rename from test/stats/samples/basic/input.html
rename to test/stats/samples/basic/input.svelte
diff --git a/test/stats/samples/duplicate-globals/input.html b/test/stats/samples/duplicate-globals/input.svelte
similarity index 100%
rename from test/stats/samples/duplicate-globals/input.html
rename to test/stats/samples/duplicate-globals/input.svelte
diff --git a/test/stats/samples/duplicate-non-hoistable/input.html b/test/stats/samples/duplicate-non-hoistable/input.svelte
similarity index 100%
rename from test/stats/samples/duplicate-non-hoistable/input.html
rename to test/stats/samples/duplicate-non-hoistable/input.svelte
diff --git a/test/stats/samples/duplicate-vars/input.html b/test/stats/samples/duplicate-vars/input.svelte
similarity index 100%
rename from test/stats/samples/duplicate-vars/input.html
rename to test/stats/samples/duplicate-vars/input.svelte
diff --git a/test/stats/samples/implicit-action/input.html b/test/stats/samples/implicit-action/input.svelte
similarity index 100%
rename from test/stats/samples/implicit-action/input.html
rename to test/stats/samples/implicit-action/input.svelte
diff --git a/test/stats/samples/implicit-reactive/input.html b/test/stats/samples/implicit-reactive/input.svelte
similarity index 100%
rename from test/stats/samples/implicit-reactive/input.html
rename to test/stats/samples/implicit-reactive/input.svelte
diff --git a/test/stats/samples/implicit/input.html b/test/stats/samples/implicit/input.svelte
similarity index 100%
rename from test/stats/samples/implicit/input.html
rename to test/stats/samples/implicit/input.svelte
diff --git a/test/stats/samples/imports/input.html b/test/stats/samples/imports/input.svelte
similarity index 100%
rename from test/stats/samples/imports/input.html
rename to test/stats/samples/imports/input.svelte
diff --git a/test/stats/samples/mutated-vs-reassigned-bindings/input.html b/test/stats/samples/mutated-vs-reassigned-bindings/input.svelte
similarity index 100%
rename from test/stats/samples/mutated-vs-reassigned-bindings/input.html
rename to test/stats/samples/mutated-vs-reassigned-bindings/input.svelte
diff --git a/test/stats/samples/mutated-vs-reassigned/input.html b/test/stats/samples/mutated-vs-reassigned/input.svelte
similarity index 100%
rename from test/stats/samples/mutated-vs-reassigned/input.html
rename to test/stats/samples/mutated-vs-reassigned/input.svelte
diff --git a/test/stats/samples/props/input.html b/test/stats/samples/props/input.svelte
similarity index 100%
rename from test/stats/samples/props/input.html
rename to test/stats/samples/props/input.svelte
diff --git a/test/stats/samples/store-referenced/input.html b/test/stats/samples/store-referenced/input.svelte
similarity index 100%
rename from test/stats/samples/store-referenced/input.html
rename to test/stats/samples/store-referenced/input.svelte
diff --git a/test/stats/samples/store-unreferenced/input.html b/test/stats/samples/store-unreferenced/input.svelte
similarity index 100%
rename from test/stats/samples/store-unreferenced/input.html
rename to test/stats/samples/store-unreferenced/input.svelte
diff --git a/test/stats/samples/template-references/input.html b/test/stats/samples/template-references/input.svelte
similarity index 100%
rename from test/stats/samples/template-references/input.html
rename to test/stats/samples/template-references/input.svelte
diff --git a/test/stats/samples/undeclared/input.html b/test/stats/samples/undeclared/input.svelte
similarity index 100%
rename from test/stats/samples/undeclared/input.html
rename to test/stats/samples/undeclared/input.svelte
diff --git a/test/validator/samples/a11y-alt-text/input.html b/test/validator/samples/a11y-alt-text/input.svelte
similarity index 100%
rename from test/validator/samples/a11y-alt-text/input.html
rename to test/validator/samples/a11y-alt-text/input.svelte
diff --git a/test/validator/samples/a11y-anchor-has-content/input.html b/test/validator/samples/a11y-anchor-has-content/input.svelte
similarity index 100%
rename from test/validator/samples/a11y-anchor-has-content/input.html
rename to test/validator/samples/a11y-anchor-has-content/input.svelte
diff --git a/test/validator/samples/a11y-anchor-in-svg-is-valid/input.html b/test/validator/samples/a11y-anchor-in-svg-is-valid/input.svelte
similarity index 100%
rename from test/validator/samples/a11y-anchor-in-svg-is-valid/input.html
rename to test/validator/samples/a11y-anchor-in-svg-is-valid/input.svelte
diff --git a/test/validator/samples/a11y-anchor-is-valid/input.html b/test/validator/samples/a11y-anchor-is-valid/input.svelte
similarity index 100%
rename from test/validator/samples/a11y-anchor-is-valid/input.html
rename to test/validator/samples/a11y-anchor-is-valid/input.svelte
diff --git a/test/validator/samples/a11y-aria-props/input.html b/test/validator/samples/a11y-aria-props/input.svelte
similarity index 100%
rename from test/validator/samples/a11y-aria-props/input.html
rename to test/validator/samples/a11y-aria-props/input.svelte
diff --git a/test/validator/samples/a11y-aria-role/input.html b/test/validator/samples/a11y-aria-role/input.svelte
similarity index 100%
rename from test/validator/samples/a11y-aria-role/input.html
rename to test/validator/samples/a11y-aria-role/input.svelte
diff --git a/test/validator/samples/a11y-aria-unsupported-element/input.html b/test/validator/samples/a11y-aria-unsupported-element/input.svelte
similarity index 100%
rename from test/validator/samples/a11y-aria-unsupported-element/input.html
rename to test/validator/samples/a11y-aria-unsupported-element/input.svelte
diff --git a/test/validator/samples/a11y-figcaption-right-place/input.html b/test/validator/samples/a11y-figcaption-right-place/input.svelte
similarity index 100%
rename from test/validator/samples/a11y-figcaption-right-place/input.html
rename to test/validator/samples/a11y-figcaption-right-place/input.svelte
diff --git a/test/validator/samples/a11y-figcaption-wrong-place/input.html b/test/validator/samples/a11y-figcaption-wrong-place/input.svelte
similarity index 100%
rename from test/validator/samples/a11y-figcaption-wrong-place/input.html
rename to test/validator/samples/a11y-figcaption-wrong-place/input.svelte
diff --git a/test/validator/samples/a11y-heading-has-content/input.html b/test/validator/samples/a11y-heading-has-content/input.svelte
similarity index 100%
rename from test/validator/samples/a11y-heading-has-content/input.html
rename to test/validator/samples/a11y-heading-has-content/input.svelte
diff --git a/test/validator/samples/a11y-html-has-lang/input.html b/test/validator/samples/a11y-html-has-lang/input.svelte
similarity index 100%
rename from test/validator/samples/a11y-html-has-lang/input.html
rename to test/validator/samples/a11y-html-has-lang/input.svelte
diff --git a/test/validator/samples/a11y-iframe-has-title/input.html b/test/validator/samples/a11y-iframe-has-title/input.svelte
similarity index 100%
rename from test/validator/samples/a11y-iframe-has-title/input.html
rename to test/validator/samples/a11y-iframe-has-title/input.svelte
diff --git a/test/validator/samples/a11y-no-access-key/input.html b/test/validator/samples/a11y-no-access-key/input.svelte
similarity index 100%
rename from test/validator/samples/a11y-no-access-key/input.html
rename to test/validator/samples/a11y-no-access-key/input.svelte
diff --git a/test/validator/samples/a11y-no-autofocus/input.html b/test/validator/samples/a11y-no-autofocus/input.svelte
similarity index 100%
rename from test/validator/samples/a11y-no-autofocus/input.html
rename to test/validator/samples/a11y-no-autofocus/input.svelte
diff --git a/test/validator/samples/a11y-no-distracting-elements/input.html b/test/validator/samples/a11y-no-distracting-elements/input.svelte
similarity index 100%
rename from test/validator/samples/a11y-no-distracting-elements/input.html
rename to test/validator/samples/a11y-no-distracting-elements/input.svelte
diff --git a/test/validator/samples/a11y-not-on-components/input.html b/test/validator/samples/a11y-not-on-components/input.svelte
similarity index 64%
rename from test/validator/samples/a11y-not-on-components/input.html
rename to test/validator/samples/a11y-not-on-components/input.svelte
index e0ee327280..c7673a67ed 100644
--- a/test/validator/samples/a11y-not-on-components/input.html
+++ b/test/validator/samples/a11y-not-on-components/input.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Widget from './Widget.html';
+	import Widget from './Widget.svelte';
 </script>
 
 <Widget scope="foo">
diff --git a/test/validator/samples/a11y-scope/input.html b/test/validator/samples/a11y-scope/input.svelte
similarity index 100%
rename from test/validator/samples/a11y-scope/input.html
rename to test/validator/samples/a11y-scope/input.svelte
diff --git a/test/validator/samples/a11y-tabindex-no-positive/input.html b/test/validator/samples/a11y-tabindex-no-positive/input.svelte
similarity index 100%
rename from test/validator/samples/a11y-tabindex-no-positive/input.html
rename to test/validator/samples/a11y-tabindex-no-positive/input.svelte
diff --git a/test/validator/samples/action-invalid/input.html b/test/validator/samples/action-invalid/input.svelte
similarity index 100%
rename from test/validator/samples/action-invalid/input.html
rename to test/validator/samples/action-invalid/input.svelte
diff --git a/test/validator/samples/action-on-component/input.html b/test/validator/samples/action-on-component/input.html
deleted file mode 100644
index 788bedaa94..0000000000
--- a/test/validator/samples/action-on-component/input.html
+++ /dev/null
@@ -1,7 +0,0 @@
-<script>
-	import Widget from './Widget.html';
-
-	function foo(){}
-</script>
-
-<Widget use:foo/>
\ No newline at end of file
diff --git a/test/validator/samples/action-on-component/input.svelte b/test/validator/samples/action-on-component/input.svelte
new file mode 100644
index 0000000000..a067c05dbd
--- /dev/null
+++ b/test/validator/samples/action-on-component/input.svelte
@@ -0,0 +1,7 @@
+<script>
+	import Widget from './Widget.svelte';
+
+	function foo(){}
+</script>
+
+<Widget use:foo/>
\ No newline at end of file
diff --git a/test/validator/samples/animation-duplicate/input.html b/test/validator/samples/animation-duplicate/input.svelte
similarity index 100%
rename from test/validator/samples/animation-duplicate/input.html
rename to test/validator/samples/animation-duplicate/input.svelte
diff --git a/test/validator/samples/animation-missing/input.html b/test/validator/samples/animation-missing/input.svelte
similarity index 100%
rename from test/validator/samples/animation-missing/input.html
rename to test/validator/samples/animation-missing/input.svelte
diff --git a/test/validator/samples/animation-not-in-each/input.html b/test/validator/samples/animation-not-in-each/input.svelte
similarity index 100%
rename from test/validator/samples/animation-not-in-each/input.html
rename to test/validator/samples/animation-not-in-each/input.svelte
diff --git a/test/validator/samples/animation-not-in-keyed-each/input.html b/test/validator/samples/animation-not-in-keyed-each/input.svelte
similarity index 100%
rename from test/validator/samples/animation-not-in-keyed-each/input.html
rename to test/validator/samples/animation-not-in-keyed-each/input.svelte
diff --git a/test/validator/samples/animation-siblings/input.html b/test/validator/samples/animation-siblings/input.svelte
similarity index 100%
rename from test/validator/samples/animation-siblings/input.html
rename to test/validator/samples/animation-siblings/input.svelte
diff --git a/test/validator/samples/await-component-is-used/input.html b/test/validator/samples/await-component-is-used/input.svelte
similarity index 77%
rename from test/validator/samples/await-component-is-used/input.html
rename to test/validator/samples/await-component-is-used/input.svelte
index 029b549675..5fe87e0c70 100644
--- a/test/validator/samples/await-component-is-used/input.html
+++ b/test/validator/samples/await-component-is-used/input.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Component from './Component.html';
+	import Component from './Component.svelte';
 
 	export let promise;
 </script>
diff --git a/test/validator/samples/binding-dimensions-svg-child/input.html b/test/validator/samples/binding-dimensions-svg-child/input.svelte
similarity index 100%
rename from test/validator/samples/binding-dimensions-svg-child/input.html
rename to test/validator/samples/binding-dimensions-svg-child/input.svelte
diff --git a/test/validator/samples/binding-dimensions-svg/input.html b/test/validator/samples/binding-dimensions-svg/input.svelte
similarity index 100%
rename from test/validator/samples/binding-dimensions-svg/input.html
rename to test/validator/samples/binding-dimensions-svg/input.svelte
diff --git a/test/validator/samples/binding-dimensions-void/input.html b/test/validator/samples/binding-dimensions-void/input.svelte
similarity index 100%
rename from test/validator/samples/binding-dimensions-void/input.html
rename to test/validator/samples/binding-dimensions-void/input.svelte
diff --git a/test/validator/samples/binding-input-checked/input.html b/test/validator/samples/binding-input-checked/input.svelte
similarity index 100%
rename from test/validator/samples/binding-input-checked/input.html
rename to test/validator/samples/binding-input-checked/input.svelte
diff --git a/test/validator/samples/binding-input-type-boolean/input.html b/test/validator/samples/binding-input-type-boolean/input.svelte
similarity index 100%
rename from test/validator/samples/binding-input-type-boolean/input.html
rename to test/validator/samples/binding-input-type-boolean/input.svelte
diff --git a/test/validator/samples/binding-input-type-dynamic/input.html b/test/validator/samples/binding-input-type-dynamic/input.svelte
similarity index 100%
rename from test/validator/samples/binding-input-type-dynamic/input.html
rename to test/validator/samples/binding-input-type-dynamic/input.svelte
diff --git a/test/validator/samples/binding-invalid-on-element/input.html b/test/validator/samples/binding-invalid-on-element/input.svelte
similarity index 100%
rename from test/validator/samples/binding-invalid-on-element/input.html
rename to test/validator/samples/binding-invalid-on-element/input.svelte
diff --git a/test/validator/samples/binding-invalid-value/input.html b/test/validator/samples/binding-invalid-value/input.svelte
similarity index 100%
rename from test/validator/samples/binding-invalid-value/input.html
rename to test/validator/samples/binding-invalid-value/input.svelte
diff --git a/test/validator/samples/binding-invalid/input.html b/test/validator/samples/binding-invalid/input.svelte
similarity index 100%
rename from test/validator/samples/binding-invalid/input.html
rename to test/validator/samples/binding-invalid/input.svelte
diff --git a/test/validator/samples/binding-select-multiple-dynamic/input.html b/test/validator/samples/binding-select-multiple-dynamic/input.svelte
similarity index 100%
rename from test/validator/samples/binding-select-multiple-dynamic/input.html
rename to test/validator/samples/binding-select-multiple-dynamic/input.svelte
diff --git a/test/validator/samples/component-slot-default-duplicate.skip/input.html b/test/validator/samples/component-slot-default-duplicate.skip/input.svelte
similarity index 100%
rename from test/validator/samples/component-slot-default-duplicate.skip/input.html
rename to test/validator/samples/component-slot-default-duplicate.skip/input.svelte
diff --git a/test/validator/samples/component-slot-default-reserved/input.html b/test/validator/samples/component-slot-default-reserved/input.svelte
similarity index 100%
rename from test/validator/samples/component-slot-default-reserved/input.html
rename to test/validator/samples/component-slot-default-reserved/input.svelte
diff --git a/test/validator/samples/component-slot-dynamic-attribute/input.html b/test/validator/samples/component-slot-dynamic-attribute/input.svelte
similarity index 58%
rename from test/validator/samples/component-slot-dynamic-attribute/input.html
rename to test/validator/samples/component-slot-dynamic-attribute/input.svelte
index 83e1df8aa2..1eb8b4f1f0 100644
--- a/test/validator/samples/component-slot-dynamic-attribute/input.html
+++ b/test/validator/samples/component-slot-dynamic-attribute/input.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Nested from './Nested.html';
+	import Nested from './Nested.svelte';
 </script>
 
 <Nested>
diff --git a/test/validator/samples/component-slot-dynamic/input.html b/test/validator/samples/component-slot-dynamic/input.svelte
similarity index 100%
rename from test/validator/samples/component-slot-dynamic/input.html
rename to test/validator/samples/component-slot-dynamic/input.svelte
diff --git a/test/validator/samples/component-slot-named-duplicate.skip/input.html b/test/validator/samples/component-slot-named-duplicate.skip/input.svelte
similarity index 100%
rename from test/validator/samples/component-slot-named-duplicate.skip/input.html
rename to test/validator/samples/component-slot-named-duplicate.skip/input.svelte
diff --git a/test/validator/samples/component-slotted-each-block/input.html b/test/validator/samples/component-slotted-each-block/input.svelte
similarity index 66%
rename from test/validator/samples/component-slotted-each-block/input.html
rename to test/validator/samples/component-slotted-each-block/input.svelte
index 2c053a1e6c..f000278a99 100644
--- a/test/validator/samples/component-slotted-each-block/input.html
+++ b/test/validator/samples/component-slotted-each-block/input.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Nested from './Nested.html';
+	import Nested from './Nested.svelte';
 </script>
 
 <Nested>
diff --git a/test/validator/samples/component-slotted-if-block/input.html b/test/validator/samples/component-slotted-if-block/input.svelte
similarity index 62%
rename from test/validator/samples/component-slotted-if-block/input.html
rename to test/validator/samples/component-slotted-if-block/input.svelte
index eda6bc2e13..d9159dfd60 100644
--- a/test/validator/samples/component-slotted-if-block/input.html
+++ b/test/validator/samples/component-slotted-if-block/input.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Nested from './Nested.html';
+	import Nested from './Nested.svelte';
 </script>
 
 <Nested>
diff --git a/test/validator/samples/css-invalid-global-placement/input.html b/test/validator/samples/css-invalid-global-placement/input.svelte
similarity index 100%
rename from test/validator/samples/css-invalid-global-placement/input.html
rename to test/validator/samples/css-invalid-global-placement/input.svelte
diff --git a/test/validator/samples/css-invalid-global/input.html b/test/validator/samples/css-invalid-global/input.svelte
similarity index 100%
rename from test/validator/samples/css-invalid-global/input.html
rename to test/validator/samples/css-invalid-global/input.svelte
diff --git a/test/validator/samples/debug-invalid-args/input.html b/test/validator/samples/debug-invalid-args/input.svelte
similarity index 100%
rename from test/validator/samples/debug-invalid-args/input.html
rename to test/validator/samples/debug-invalid-args/input.svelte
diff --git a/test/validator/samples/default-export/input.html b/test/validator/samples/default-export/input.svelte
similarity index 100%
rename from test/validator/samples/default-export/input.html
rename to test/validator/samples/default-export/input.svelte
diff --git a/test/validator/samples/directive-non-expression/input.html b/test/validator/samples/directive-non-expression/input.svelte
similarity index 100%
rename from test/validator/samples/directive-non-expression/input.html
rename to test/validator/samples/directive-non-expression/input.svelte
diff --git a/test/validator/samples/each-block-invalid-context-destructured/input.html b/test/validator/samples/each-block-invalid-context-destructured/input.svelte
similarity index 100%
rename from test/validator/samples/each-block-invalid-context-destructured/input.html
rename to test/validator/samples/each-block-invalid-context-destructured/input.svelte
diff --git a/test/validator/samples/each-block-invalid-context/input.html b/test/validator/samples/each-block-invalid-context/input.svelte
similarity index 100%
rename from test/validator/samples/each-block-invalid-context/input.html
rename to test/validator/samples/each-block-invalid-context/input.svelte
diff --git a/test/validator/samples/each-block-multiple-children/input.html b/test/validator/samples/each-block-multiple-children/input.svelte
similarity index 100%
rename from test/validator/samples/each-block-multiple-children/input.html
rename to test/validator/samples/each-block-multiple-children/input.svelte
diff --git a/test/validator/samples/empty-block-dev/input.html b/test/validator/samples/empty-block-dev/input.svelte
similarity index 100%
rename from test/validator/samples/empty-block-dev/input.html
rename to test/validator/samples/empty-block-dev/input.svelte
diff --git a/test/validator/samples/empty-block-prod/input.html b/test/validator/samples/empty-block-prod/input.svelte
similarity index 100%
rename from test/validator/samples/empty-block-prod/input.html
rename to test/validator/samples/empty-block-prod/input.svelte
diff --git a/test/validator/samples/event-modifiers-invalid-passive/input.html b/test/validator/samples/event-modifiers-invalid-passive/input.svelte
similarity index 100%
rename from test/validator/samples/event-modifiers-invalid-passive/input.html
rename to test/validator/samples/event-modifiers-invalid-passive/input.svelte
diff --git a/test/validator/samples/event-modifiers-invalid/input.html b/test/validator/samples/event-modifiers-invalid/input.svelte
similarity index 100%
rename from test/validator/samples/event-modifiers-invalid/input.html
rename to test/validator/samples/event-modifiers-invalid/input.svelte
diff --git a/test/validator/samples/event-modifiers-legacy/input.html b/test/validator/samples/event-modifiers-legacy/input.svelte
similarity index 100%
rename from test/validator/samples/event-modifiers-legacy/input.html
rename to test/validator/samples/event-modifiers-legacy/input.svelte
diff --git a/test/validator/samples/event-modifiers-redundant/input.html b/test/validator/samples/event-modifiers-redundant/input.svelte
similarity index 100%
rename from test/validator/samples/event-modifiers-redundant/input.html
rename to test/validator/samples/event-modifiers-redundant/input.svelte
diff --git a/test/validator/samples/missing-component/input.html b/test/validator/samples/missing-component/input.svelte
similarity index 100%
rename from test/validator/samples/missing-component/input.html
rename to test/validator/samples/missing-component/input.svelte
diff --git a/test/validator/samples/multiple-script-default-context/input.html b/test/validator/samples/multiple-script-default-context/input.svelte
similarity index 100%
rename from test/validator/samples/multiple-script-default-context/input.html
rename to test/validator/samples/multiple-script-default-context/input.svelte
diff --git a/test/validator/samples/multiple-script-module-context/input.html b/test/validator/samples/multiple-script-module-context/input.svelte
similarity index 100%
rename from test/validator/samples/multiple-script-module-context/input.html
rename to test/validator/samples/multiple-script-module-context/input.svelte
diff --git a/test/validator/samples/namespace-invalid-unguessable/input.html b/test/validator/samples/namespace-invalid-unguessable/input.svelte
similarity index 100%
rename from test/validator/samples/namespace-invalid-unguessable/input.html
rename to test/validator/samples/namespace-invalid-unguessable/input.svelte
diff --git a/test/validator/samples/namespace-invalid/input.html b/test/validator/samples/namespace-invalid/input.svelte
similarity index 100%
rename from test/validator/samples/namespace-invalid/input.html
rename to test/validator/samples/namespace-invalid/input.svelte
diff --git a/test/validator/samples/namespace-non-literal/input.html b/test/validator/samples/namespace-non-literal/input.svelte
similarity index 100%
rename from test/validator/samples/namespace-non-literal/input.html
rename to test/validator/samples/namespace-non-literal/input.svelte
diff --git a/test/validator/samples/non-empty-block-dev/input.html b/test/validator/samples/non-empty-block-dev/input.svelte
similarity index 100%
rename from test/validator/samples/non-empty-block-dev/input.html
rename to test/validator/samples/non-empty-block-dev/input.svelte
diff --git a/test/validator/samples/prop-slot/input.html b/test/validator/samples/prop-slot/input.svelte
similarity index 51%
rename from test/validator/samples/prop-slot/input.html
rename to test/validator/samples/prop-slot/input.svelte
index 6ce1b6dcce..816c656aa0 100644
--- a/test/validator/samples/prop-slot/input.html
+++ b/test/validator/samples/prop-slot/input.svelte
@@ -1,5 +1,5 @@
 <script>
-	import Widget from './Widget.html';
+	import Widget from './Widget.svelte';
 </script>
 
 <Widget slot='foo'/>
diff --git a/test/validator/samples/reactive-declaration-cyclical/input.html b/test/validator/samples/reactive-declaration-cyclical/input.svelte
similarity index 100%
rename from test/validator/samples/reactive-declaration-cyclical/input.html
rename to test/validator/samples/reactive-declaration-cyclical/input.svelte
diff --git a/test/validator/samples/ref-not-supported-in-css/input.html b/test/validator/samples/ref-not-supported-in-css/input.svelte
similarity index 100%
rename from test/validator/samples/ref-not-supported-in-css/input.html
rename to test/validator/samples/ref-not-supported-in-css/input.svelte
diff --git a/test/validator/samples/ref-not-supported/input.html b/test/validator/samples/ref-not-supported/input.svelte
similarity index 100%
rename from test/validator/samples/ref-not-supported/input.html
rename to test/validator/samples/ref-not-supported/input.svelte
diff --git a/test/validator/samples/script-invalid-context/input.html b/test/validator/samples/script-invalid-context/input.svelte
similarity index 100%
rename from test/validator/samples/script-invalid-context/input.html
rename to test/validator/samples/script-invalid-context/input.svelte
diff --git a/test/validator/samples/select-multiple/input.html b/test/validator/samples/select-multiple/input.svelte
similarity index 100%
rename from test/validator/samples/select-multiple/input.html
rename to test/validator/samples/select-multiple/input.svelte
diff --git a/test/validator/samples/slot-attribute-invalid/input.html b/test/validator/samples/slot-attribute-invalid/input.svelte
similarity index 100%
rename from test/validator/samples/slot-attribute-invalid/input.html
rename to test/validator/samples/slot-attribute-invalid/input.svelte
diff --git a/test/validator/samples/svg-child-component-declared-namespace/input.html b/test/validator/samples/svg-child-component-declared-namespace/input.svelte
similarity index 100%
rename from test/validator/samples/svg-child-component-declared-namespace/input.html
rename to test/validator/samples/svg-child-component-declared-namespace/input.svelte
diff --git a/test/validator/samples/svg-child-component-undeclared-namespace/input.html b/test/validator/samples/svg-child-component-undeclared-namespace/input.svelte
similarity index 100%
rename from test/validator/samples/svg-child-component-undeclared-namespace/input.html
rename to test/validator/samples/svg-child-component-undeclared-namespace/input.svelte
diff --git a/test/validator/samples/tag-invalid/input.html b/test/validator/samples/tag-invalid/input.svelte
similarity index 100%
rename from test/validator/samples/tag-invalid/input.html
rename to test/validator/samples/tag-invalid/input.svelte
diff --git a/test/validator/samples/tag-non-string/input.html b/test/validator/samples/tag-non-string/input.svelte
similarity index 100%
rename from test/validator/samples/tag-non-string/input.html
rename to test/validator/samples/tag-non-string/input.svelte
diff --git a/test/validator/samples/textarea-value-children/input.html b/test/validator/samples/textarea-value-children/input.svelte
similarity index 100%
rename from test/validator/samples/textarea-value-children/input.html
rename to test/validator/samples/textarea-value-children/input.svelte
diff --git a/test/validator/samples/title-no-attributes/input.html b/test/validator/samples/title-no-attributes/input.svelte
similarity index 100%
rename from test/validator/samples/title-no-attributes/input.html
rename to test/validator/samples/title-no-attributes/input.svelte
diff --git a/test/validator/samples/title-no-children/input.html b/test/validator/samples/title-no-children/input.svelte
similarity index 100%
rename from test/validator/samples/title-no-children/input.html
rename to test/validator/samples/title-no-children/input.svelte
diff --git a/test/validator/samples/transition-duplicate-in-transition/input.html b/test/validator/samples/transition-duplicate-in-transition/input.svelte
similarity index 100%
rename from test/validator/samples/transition-duplicate-in-transition/input.html
rename to test/validator/samples/transition-duplicate-in-transition/input.svelte
diff --git a/test/validator/samples/transition-duplicate-in/input.html b/test/validator/samples/transition-duplicate-in/input.svelte
similarity index 100%
rename from test/validator/samples/transition-duplicate-in/input.html
rename to test/validator/samples/transition-duplicate-in/input.svelte
diff --git a/test/validator/samples/transition-duplicate-out-transition/input.html b/test/validator/samples/transition-duplicate-out-transition/input.svelte
similarity index 100%
rename from test/validator/samples/transition-duplicate-out-transition/input.html
rename to test/validator/samples/transition-duplicate-out-transition/input.svelte
diff --git a/test/validator/samples/transition-duplicate-out/input.html b/test/validator/samples/transition-duplicate-out/input.svelte
similarity index 100%
rename from test/validator/samples/transition-duplicate-out/input.html
rename to test/validator/samples/transition-duplicate-out/input.svelte
diff --git a/test/validator/samples/transition-duplicate-transition-in/input.html b/test/validator/samples/transition-duplicate-transition-in/input.svelte
similarity index 100%
rename from test/validator/samples/transition-duplicate-transition-in/input.html
rename to test/validator/samples/transition-duplicate-transition-in/input.svelte
diff --git a/test/validator/samples/transition-duplicate-transition-out/input.html b/test/validator/samples/transition-duplicate-transition-out/input.svelte
similarity index 100%
rename from test/validator/samples/transition-duplicate-transition-out/input.html
rename to test/validator/samples/transition-duplicate-transition-out/input.svelte
diff --git a/test/validator/samples/transition-duplicate-transition/input.html b/test/validator/samples/transition-duplicate-transition/input.svelte
similarity index 100%
rename from test/validator/samples/transition-duplicate-transition/input.html
rename to test/validator/samples/transition-duplicate-transition/input.svelte
diff --git a/test/validator/samples/transition-missing/input.html b/test/validator/samples/transition-missing/input.svelte
similarity index 100%
rename from test/validator/samples/transition-missing/input.html
rename to test/validator/samples/transition-missing/input.svelte
diff --git a/test/validator/samples/transition-on-component/input.html b/test/validator/samples/transition-on-component/input.html
deleted file mode 100644
index 392f346424..0000000000
--- a/test/validator/samples/transition-on-component/input.html
+++ /dev/null
@@ -1,7 +0,0 @@
-<script>
-	import Widget from './Widget.html';
-
-	function foo() {}
-</script>
-
-<Widget in:foo/>
\ No newline at end of file
diff --git a/test/validator/samples/transition-on-component/input.svelte b/test/validator/samples/transition-on-component/input.svelte
new file mode 100644
index 0000000000..12c3cd9bf8
--- /dev/null
+++ b/test/validator/samples/transition-on-component/input.svelte
@@ -0,0 +1,7 @@
+<script>
+	import Widget from './Widget.svelte';
+
+	function foo() {}
+</script>
+
+<Widget in:foo/>
\ No newline at end of file
diff --git a/test/validator/samples/undefined-value/input.html b/test/validator/samples/undefined-value/input.svelte
similarity index 100%
rename from test/validator/samples/undefined-value/input.html
rename to test/validator/samples/undefined-value/input.svelte
diff --git a/test/validator/samples/window-binding-invalid-innerwidth/input.html b/test/validator/samples/window-binding-invalid-innerwidth/input.svelte
similarity index 100%
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