<!DOCTYPE html>
<html class=reftest-wait>
<link rel="help" href="https://drafts.css-houdini.org/css-layout-api/#invoke-a-layout-callback">
<link rel="match" href="fallback-layout-fallback-ref.html">
<meta name="assert" content="This test checks that a layout() class with a throwing layout function will fallback to block layout." />
<style>
.test {
  background: red;
  border: solid 2px;
  width: 100px;
}

.float {
  float: left;
  width: 50%;
  height: 100px;
}

.fc {
  display: flow-root;
  height: 100px;
}

@supports (display: layout(throwing-layout)) {
  .test {
    display: layout(throwing-layout);
    background: green;
  }
}
</style>
<script src="/common/reftest-wait.js"></script>
<script src="/common/worklet-reftest.js"></script>

<!-- This tests that when the "layout()" layout function fails, it will fallback to block layout. -->
<div class="test">
  <div class="float"></div>
  <div class="fc"></div>
</div>

<script id="code" type="text/worklet">
registerLayout('throwing-layout', class {
  async intrinsicSizes() {}
  async layout() { throw Error('fail!'); }
});
</script>

<script>
importWorkletAndTerminateTestAfterAsyncPaint(CSS.layoutWorklet, document.getElementById('code').textContent);
</script>
</html>