diff --git a/test/js/samples/action/expected.js b/test/js/samples/action/expected.js
index cbbcb0d317..ed0a0a7430 100644
--- a/test/js/samples/action/expected.js
+++ b/test/js/samples/action/expected.js
@@ -1,6 +1,7 @@
 /* generated by Svelte vX.Y.Z */
 import {
 	SvelteComponent,
+	attr,
 	detach,
 	element,
 	init,
@@ -16,7 +17,7 @@ function create_fragment(ctx) {
 		c() {
 			a = element("a");
 			a.textContent = "Test";
-			a.href = "#";
+			attr(a, "href", "#");
 		},
 
 		m(target, anchor) {
diff --git a/test/js/samples/collapses-text-around-comments/expected.js b/test/js/samples/collapses-text-around-comments/expected.js
index 12164d0579..09b40a1e98 100644
--- a/test/js/samples/collapses-text-around-comments/expected.js
+++ b/test/js/samples/collapses-text-around-comments/expected.js
@@ -2,6 +2,7 @@
 import {
 	SvelteComponent,
 	append,
+	attr,
 	detach,
 	element,
 	init,
@@ -26,7 +27,7 @@ function create_fragment(ctx) {
 		c() {
 			p = element("p");
 			t = text(ctx.foo);
-			p.className = "svelte-1a7i8ec";
+			attr(p, "class", "svelte-1a7i8ec");
 		},
 
 		m(target, anchor) {
diff --git a/test/js/samples/css-media-query/expected.js b/test/js/samples/css-media-query/expected.js
index d4be134376..82b7c5dfc8 100644
--- a/test/js/samples/css-media-query/expected.js
+++ b/test/js/samples/css-media-query/expected.js
@@ -2,6 +2,7 @@
 import {
 	SvelteComponent,
 	append,
+	attr,
 	detach,
 	element,
 	init,
@@ -23,7 +24,7 @@ function create_fragment(ctx) {
 	return {
 		c() {
 			div = element("div");
-			div.className = "svelte-1slhpfn";
+			attr(div, "class", "svelte-1slhpfn");
 		},
 
 		m(target, anchor) {
diff --git a/test/js/samples/each-block-changed-check/expected.js b/test/js/samples/each-block-changed-check/expected.js
index 951565bae4..b4d4577df3 100644
--- a/test/js/samples/each-block-changed-check/expected.js
+++ b/test/js/samples/each-block-changed-check/expected.js
@@ -2,6 +2,7 @@
 import {
 	SvelteComponent,
 	append,
+	attr,
 	destroy_each,
 	detach,
 	detach_after,
@@ -39,8 +40,8 @@ function create_each_block(ctx) {
 			t5 = text(" ago:");
 			t6 = space();
 			raw_before = element('noscript');
-			span.className = "meta";
-			div.className = "comment";
+			attr(span, "class", "meta");
+			attr(div, "class", "comment");
 		},
 
 		m(target, anchor) {
diff --git a/test/js/samples/event-handler-no-passive/expected.js b/test/js/samples/event-handler-no-passive/expected.js
index 41fcbeeb2a..e8ca72c556 100644
--- a/test/js/samples/event-handler-no-passive/expected.js
+++ b/test/js/samples/event-handler-no-passive/expected.js
@@ -1,6 +1,7 @@
 /* generated by Svelte vX.Y.Z */
 import {
 	SvelteComponent,
+	attr,
 	detach,
 	element,
 	init,
@@ -17,7 +18,7 @@ function create_fragment(ctx) {
 		c() {
 			a = element("a");
 			a.textContent = "this should not navigate to example.com";
-			a.href = "https://example.com";
+			attr(a, "href", "https://example.com");
 			dispose = listen(a, "touchstart", touchstart_handler);
 		},
 
diff --git a/test/js/samples/head-no-whitespace/expected.js b/test/js/samples/head-no-whitespace/expected.js
index b95177bba7..457df77dc8 100644
--- a/test/js/samples/head-no-whitespace/expected.js
+++ b/test/js/samples/head-no-whitespace/expected.js
@@ -2,6 +2,7 @@
 import {
 	SvelteComponent,
 	append,
+	attr,
 	detach,
 	element,
 	init,
@@ -16,10 +17,10 @@ function create_fragment(ctx) {
 		c() {
 			meta0 = element("meta");
 			meta1 = element("meta");
-			meta0.name = "twitter:creator";
-			meta0.content = "@sveltejs";
-			meta1.name = "twitter:title";
-			meta1.content = "Svelte";
+			attr(meta0, "name", "twitter:creator");
+			attr(meta0, "content", "@sveltejs");
+			attr(meta1, "name", "twitter:title");
+			attr(meta1, "content", "Svelte");
 		},
 
 		m(target, anchor) {
diff --git a/test/js/samples/inline-style-unoptimized/expected.js b/test/js/samples/inline-style-unoptimized/expected.js
index 8f3b668827..9349ade12c 100644
--- a/test/js/samples/inline-style-unoptimized/expected.js
+++ b/test/js/samples/inline-style-unoptimized/expected.js
@@ -1,6 +1,7 @@
 /* generated by Svelte vX.Y.Z */
 import {
 	SvelteComponent,
+	attr,
 	detach,
 	element,
 	init,
@@ -18,8 +19,8 @@ function create_fragment(ctx) {
 			div0 = element("div");
 			t = space();
 			div1 = element("div");
-			div0.style.cssText = ctx.style;
-			div1.style.cssText = div1_style_value = "" + ctx.key + ": " + ctx.value;
+			attr(div0, "style", ctx.style);
+			attr(div1, "style", div1_style_value = "" + ctx.key + ": " + ctx.value);
 		},
 
 		m(target, anchor) {
@@ -30,11 +31,11 @@ function create_fragment(ctx) {
 
 		p(changed, ctx) {
 			if (changed.style) {
-				div0.style.cssText = ctx.style;
+				attr(div0, "style", ctx.style);
 			}
 
 			if ((changed.key || changed.value) && div1_style_value !== (div1_style_value = "" + ctx.key + ": " + ctx.value)) {
-				div1.style.cssText = div1_style_value;
+				attr(div1, "style", div1_style_value);
 			}
 		},
 
diff --git a/test/runtime/samples/contenteditable-html/_config.js b/test/runtime/samples/contenteditable-html/_config.js
index 013fa30f39..285512b6c9 100644
--- a/test/runtime/samples/contenteditable-html/_config.js
+++ b/test/runtime/samples/contenteditable-html/_config.js
@@ -4,7 +4,7 @@ export default {
 	},
 
 	html: `
-		<editor><b>world</b></editor>
+		<editor contenteditable="true"><b>world</b></editor>
 		<p>hello <b>world</b></p>
 	`,
 
@@ -21,7 +21,7 @@ export default {
 
 		// No updates to data yet
 		assert.htmlEqual(target.innerHTML, `
-			<editor>every<span>body</span></editor>
+			<editor contenteditable="true">every<span>body</span></editor>
 			<p>hello <b>world</b></p>
 		`);
 
@@ -29,14 +29,14 @@ export default {
 		const event = new window.Event('input');
 		await el.dispatchEvent(event);
 		assert.htmlEqual(target.innerHTML, `
-			<editor>every<span>body</span></editor>
+			<editor contenteditable="true">every<span>body</span></editor>
 			<p>hello every<span>body</span></p>
 		`);
 
 		component.name = 'good<span>bye</span>';
 		assert.equal(el.innerHTML, 'good<span>bye</span>');
 		assert.htmlEqual(target.innerHTML, `
-			<editor>good<span>bye</span></editor>
+			<editor contenteditable="true">good<span>bye</span></editor>
 			<p>hello good<span>bye</span></p>
 		`);
 	},
diff --git a/test/runtime/samples/contenteditable-text/_config.js b/test/runtime/samples/contenteditable-text/_config.js
index 4935a3a9a7..059cda7cfe 100644
--- a/test/runtime/samples/contenteditable-text/_config.js
+++ b/test/runtime/samples/contenteditable-text/_config.js
@@ -4,7 +4,7 @@ export default {
 	},
 
 	html: `
-		<editor>world</editor>
+		<editor contenteditable="true">world</editor>
 		<p>hello world</p>
 	`,
 
@@ -23,14 +23,14 @@ export default {
 		await el.dispatchEvent(event);
 
 		assert.htmlEqual(target.innerHTML, `
-			<editor>everybody</editor>
+			<editor contenteditable="true">everybody</editor>
 			<p>hello everybody</p>
 		`);
 
 		component.name = 'goodbye';
 		assert.equal(el.textContent, 'goodbye');
 		assert.htmlEqual(target.innerHTML, `
-			<editor>goodbye</editor>
+			<editor contenteditable="true">goodbye</editor>
 			<p>hello goodbye</p>
 		`);
 	},
diff --git a/test/runtime/samples/set-undefined-attr/_config.js b/test/runtime/samples/set-undefined-attr/_config.js
index e28bad8257..b23f51dfc9 100644
--- a/test/runtime/samples/set-undefined-attr/_config.js
+++ b/test/runtime/samples/set-undefined-attr/_config.js
@@ -1,5 +1,5 @@
 export default {
-	html: '<div></div>',
+	html: `<div draggable='false'></div>`,
 
-	ssrHtml: '<div foo=1></div>'
+	ssrHtml: `<div foo='1' draggable='false'></div>`,
 };
diff --git a/test/runtime/samples/set-undefined-attr/main.svelte b/test/runtime/samples/set-undefined-attr/main.svelte
index 8191acbeff..77a1885415 100644
--- a/test/runtime/samples/set-undefined-attr/main.svelte
+++ b/test/runtime/samples/set-undefined-attr/main.svelte
@@ -3,10 +3,11 @@
 
 	export let foo = 1;
 	export let bar;
+	export let _class;
 
 	onMount(() => {
 		foo = undefined;
 	});
 </script>
 
-<div {foo} {bar}></div>
+<div {foo} {bar} class={_class} draggable='false'></div>