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+++ b/testing/web-platform/tests/layout-instability/transform-counter-layout-shift.html
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+<!DOCTYPE html>
+<title>Layout Instability: no layout shift if transform change counters location change</title>
+<link rel="help" href="https://wicg.github.io/layout-instability/" />
+<style>
+body { margin: 0; }
+#transformed { position: relative; transform: translateX(20px); width: 100px; height: 100px; background: blue; }
+#child { width: 400px; height: 400px; }
+</style>
+<div id="transformed">
+  <div id="child"></div>
+</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);
+
+  // Modify the transform and the location at the same time, and the values
+  // cancel each other visually, for which no shift should be reported.
+  transformed.style.transform = 'translateY(100px)';
+  transformed.style.top = '-100px';
+  transformed.style.left = '20px';
+  // Change size of child, for which no shift should be reported, either.
+  child.style.width = '300px';
+
+  await waitForAnimationFrames(2);
+  // No shift should be reported.
+  assert_equals(watcher.score, 0);
+}, 'no layout shift if transform change counters location change');
+
+</script>