<!DOCTYPE html>
<title>Layout Instability: movement distance uses starting corner</title>
<link rel="help" href="https://wicg.github.io/layout-instability/" />
<style>

#shifter { position: relative; width: 100px; height: 100px; direction: rtl; background: blue; }

</style>
<div id='shifter'></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 the left edge rightward by 10px and the right edge leftward by 20px.
  document.querySelector("#shifter").style = "width: 70px; left: 10px";

  // The movement distance should use the displacement of the right edge.
  const expectedScore = computeExpectedScore(100 * 100, 20);

  await watcher.promise;
  assert_equals(watcher.score, expectedScore);
}, 'RTL element.');

</script>