| <!DOCTYPE html> |
| <title>Layout Instability: simple block movement is detected</title> |
| <link rel="help" href="https://wicg.github.io/layout-instability/" /> |
| <style> |
| |
| #shifter { position: relative; width: 300px; height: 100px; } |
| |
| </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); |
| |
| // Modify the position of the div. |
| document.querySelector("#shifter").style = "top: 60px"; |
| |
| // An element of size (300 x 100) has shifted by 60px. |
| const expectedScore = computeExpectedScore(300 * (100 + 60), 60); |
| |
| // Observer fires after the frame is painted. |
| assert_equals(watcher.score, 0); |
| await watcher.promise; |
| assert_equals(watcher.score, expectedScore); |
| }, 'Simple block movement.'); |
| |
| </script> |
