<!DOCTYPE html>
<title>Layout Instability: ignore fixed and sticky positioning</title>
<link rel="help" href="https://wicg.github.io/layout-instability/" />
<style>

body { height: 2000px; }
#f1, #f2 {
  position: fixed;
  width: 300px;
  height: 100px;
  left: 100px;
  background: yellow;
}
#f1 { top: 0; }
#f2 { top: 150px; will-change: transform; }
#s1 {
  position: sticky;
  width: 200px;
  height: 100px;
  left: 450px;
  top: 0;
  background: blue;
}

</style>
<div id='f1'>fixed</div>
<div id='f2'>fixed composited</div>
<div id='s1'>sticky</div>
normal

<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="resources/util.js"></script>
<script>

promise_test(async () => {
  const watcher = new ScoreWatcher;

  // Wait for the initial render to complete.
  await waitForAnimationFrames(2);

  // Scroll down by 50px.
  document.scrollingElement.scrollTop = 50;

  // Force a layout.
  document.body.style.height = "2500px";

  // No layout shift should occur as a result of the scroll-triggered
  // repositioning of fixed and sticky elements.
  await waitForAnimationFrames(3);
  assert_equals(watcher.score, 0);
}, 'Ignore fixed and sticky.');

</script>
