layout-instability/opacity-zero.html

<!DOCTYPE html>
<title>Layout Instability: opacity:0</title>
<link rel="help" href="https://wicg.github.io/layout-instability/" />
<div id="target" style="position: absolute; top: 0; width: 400px; height: 400px; opacity: 0; background: blue">
  <div id="child" style="position: relative; top: 0; width: 200px; height: 200px; opacity: 0.5; background: yellow"></div>
</div>
<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);

  // Shift target, for which no shift should be reported because it's not visible.
  target.style.top = '200px';

  await waitForAnimationFrames(2);
  assert_equals(watcher.score, 0);

  // Shift child, for which no shift should be reported, either.
  child.style.top = '100px';

  await waitForAnimationFrames(2);
  assert_equals(watcher.score, 0);
}, 'opacity:0');

</script>