layout-instability/video.html

<!DOCTYPE html>
<title>Layout Instability: no shifts from advancing video track</title>
<link rel="help" href="https://wicg.github.io/layout-instability/" />
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="resources/test-adapter.js"></script>
<script src="resources/util.js"></script>
<video controls>
  <source src="/media/white.webm" type="video/webm">
</video>
<script>

promise_test(async () => {
  const watcher = new ScoreWatcher;
  var video = document.querySelector("video");

  await new Promise(resolve => { video.oncanplay = resolve; });
  await waitForAnimationFrames(2);

  // TODO(crbug.com/1088311): There are still some shifts from creating the
  // <video>, so the score is already > 0 here. For now, just verify that
  // advancing the track does not increase it further.
  var currentScore = watcher.score;

  video.currentTime = 5;

  await waitForAnimationFrames(3);
  cls_expect(watcher, {score: currentScore});

}, "No shifts from advancing video track.");

</script>