<!DOCTYPE html>
<title>Layout Instability: visibility:hidden change with layout</title>
<link rel="help" href="https://wicg.github.io/layout-instability/" />
<div id="target" style="position: absolute; top: 0; width: 200px; height: 200px; visibility: hidden; background: blue"></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 hidden.
target.style.top = '200px';
target.style.visibility = 'visible';
await waitForAnimationFrames(2);
// No shift should be reported.
assert_equals(watcher.score, 0);
// Shift again, for which shift should be reported.
target.style.top = '300px';
await watcher.promise;
const expectedScore = computeExpectedScore(200 * (200 + 100), 100);
assert_equals(watcher.score, expectedScore);
}, 'visibility:hidden change with layout');
</script>