layout-instability/multicol-001.html

<!DOCTYPE html>
<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/util.js"></script>
<div id="multicol" style="position:relative; columns:5; column-gap:0; column-gap:0; width:500px; height:1px;">
  <div style="contain:size; height:100px; background:hotpink;"></div>
  <div style="contain:size; height:100px; background:hotpink;"></div>
  <div style="contain:size; height:100px; background:hotpink;"></div>
  <div style="contain:size; height:100px; background:hotpink;"></div>
  <div style="contain:size; height:100px; background:hotpink;"></div>
</div>
<script>

promise_test(async () => {
  const watcher = new ScoreWatcher;
  await waitForAnimationFrames(2);

  multicol.style.top = '100px';
  const expectedScore = computeExpectedScore(500 * (100 + 100), 100);

  await watcher.promise;
  assert_equals(watcher.score, expectedScore);
}, 'Move multicol container with overflow');

</script>