diff --git a/test/runtime/samples/binding-width-height-z-index/_config.js b/test/runtime/samples/binding-width-height-z-index/_config.js
new file mode 100644
index 0000000000..423289f8d3
--- /dev/null
+++ b/test/runtime/samples/binding-width-height-z-index/_config.js
@@ -0,0 +1,7 @@
+export default {
+  async test({ assert, target }) {
+    const iframe = target.querySelector('iframe');
+
+    assert.equal(iframe.style.zIndex, '-1');
+  }
+};
diff --git a/test/runtime/samples/binding-width-height-z-index/main.svelte b/test/runtime/samples/binding-width-height-z-index/main.svelte
new file mode 100644
index 0000000000..bc14bd33f8
--- /dev/null
+++ b/test/runtime/samples/binding-width-height-z-index/main.svelte
@@ -0,0 +1,8 @@
+<script>
+	let offsetWidth = 0;
+	let offsetHeight = 0;
+</script>
+
+<div style="z-index: 42;" bind:offsetHeight bind:offsetWidth>
+	<h1>Hello</h1>
+</div>