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Test Info: Warnings

<!DOCTYPE html>
<title>Layout Instability: no layout shift for change of individual transform property</title>
<link rel="help" href="" />
body { margin: 0; }
#transformed { position: relative; translate: 20px 0; width: 100px; height: 100px; background: blue; }
#child { width: 400px; height: 400px; }
<div id="transformed">
<div id="child"></div>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="resources/util.js"></script>
promise_test(async () => {
const watcher = new ScoreWatcher;
// Wait for the initial render to complete.
await waitForAnimationFrames(2);
// Modify the transform, for which no shift should be reported.
document.querySelector("#transformed").style = "translate: 0 100px";
// Change size of child, for which no shift should be reported, either.
document.querySelector("#child").style = "width: 300px";
await waitForAnimationFrames(2);
// No shift should be reported.
assert_equals(watcher.score, 0);
}, 'no layout shift for transform change');