shift-into-viewport-inline-direction.html

<!DOCTYPE html>
<title>Layout Instability: shift into viewport in inline direction</title>
<link rel="help" href="https://wicg.github.io/layout-instability/" />
<style>
#j { position: absolute; width: 200px; height: 600px; left: -200px; background: blue; }
</style>
<div id='j'></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);

  // Move div into viewport horizontally.
  document.querySelector("#j").style.left = '100px';

  await waitForAnimationFrames(3);
  assert_equals(watcher.score, 0);
}, "Shift into viewport in inline direction.");

</script>

chromium/third_party/blink/web_tests/external/wpt/layout-instability/shift-into-viewport-inline-direction.html