| <!DOCTYPE HTML> |
| <meta charset=utf-8> |
| <title>Largest Contentful Paint: observe text.</title> |
| <body> |
| <script src="/resources/testharness.js"></script> |
| <script src="/resources/testharnessreport.js"></script> |
| <style> |
| p { |
| font-size: 12px; |
| } |
| </style> |
| <script> |
| async_test(function (t) { |
| assert_precondition(window.LargestContentfulPaint, "LargestContentfulPaint is not implemented"); |
| let beforeRender; |
| const observer = new PerformanceObserver( |
| t.step_func_done(function(entryList) { |
| assert_equals(entryList.getEntries().length, 1); |
| const entry = entryList.getEntries()[0]; |
| assert_equals(entry.entryType, 'largest-contentful-paint'); |
| assert_greater_than_equal(entry.renderTime, beforeRender); |
| assert_greater_than_equal(performance.now(), entry.renderTime); |
| assert_equals(entry.startTime, entry.renderTime, 'startTime should equal renderTime'); |
| assert_equals(entry.duration, 0); |
| // Some lower bound: height of at least 12 px. |
| // Width of at least 100 px. |
| // TODO: find a good way to bound text width. |
| assert_greater_than_equal(entry.size, 1200); |
| assert_equals(entry.loadTime, 0); |
| assert_equals(entry.id, 'my_text'); |
| assert_equals(entry.url, ''); |
| assert_equals(entry.element, document.getElementById('my_text')); |
| }) |
| ); |
| observer.observe({type: 'largest-contentful-paint', buffered: true}); |
| beforeRender = performance.now(); |
| }, 'Element with elementtiming attribute is observable.'); |
| </script> |
| |
| <p id='my_text'>This is important text! :)</p> |
| </body> |
