| <!DOCTYPE HTML> |
| <meta charset=utf-8> |
| <title>Largest Contentful Paint: observe text with display style.</title> |
| <body> |
| <script src="/resources/testharness.js"></script> |
| <script src="/resources/testharnessreport.js"></script> |
| <style> |
| #title { |
| display: flex; |
| } |
| </style> |
| <h1 id='title'>I am a title!</h1> |
| <script> |
| async_test(function (t) { |
| assert_implements(window.LargestContentfulPaint, "LargestContentfulPaint is not implemented"); |
| let beforeRender; |
| /* In this test, we first observe a header with style 'display: flex'. |
| * Once observed, we remove it and add a header with style 'display: grid'. |
| * And once that is observed, we remove it and add a header with style 'display: block'. |
| * At each step, we check the values of the entries received. |
| */ |
| let observedFlex = false; |
| let observedGrid = false; |
| const observer = new PerformanceObserver( |
| t.step_func(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_approx_equals(entry.startTime, entry.renderTime, 0.001, |
| 'startTime should be equal to renderTime to the precision of 1 millisecond.'); |
| assert_equals(entry.duration, 0); |
| // TODO: find a good way to bound text size. |
| assert_greater_than_equal(entry.size, 500); |
| assert_equals(entry.url, ''); |
| assert_equals(entry.loadTime, 0); |
| if (!observedFlex) { |
| observedFlex = true; |
| assert_equals(entry.id, 'title'); |
| const title = document.getElementById('title'); |
| assert_equals(entry.element, title); |
| // Remove 'display: flex' and add 'display: grid' text. |
| title.parentNode.removeChild(title); |
| const title2 = document.createElement('h1'); |
| title2.id = 'title2'; |
| title2.style = 'display: grid'; |
| title2.innerHTML = 'I am a second title!'; |
| document.body.appendChild(title2); |
| beforeRender = performance.now(); |
| } else if (!observedGrid) { |
| observedGrid = true; |
| assert_equals(entry.id, 'title2'); |
| const title2 = document.getElementById('title2'); |
| assert_equals(entry.element, title2); |
| // Remove 'display: grid' and add 'display: block' text. |
| title2.parentNode.removeChild(title2); |
| const title3 = document.createElement('h1'); |
| title3.id = 'title3'; |
| title3.style = 'display: block'; |
| title3.innerHTML = 'I am the third and last title!'; |
| document.body.appendChild(title3); |
| beforeRender = performance.now(); |
| } else { |
| assert_equals(entry.id, 'title3'); |
| const title3 = document.getElementById('title3'); |
| assert_equals(entry.element, title3); |
| t.done(); |
| } |
| }) |
| ); |
| observer.observe({type: 'largest-contentful-paint', buffered: true}); |
| beforeRender = performance.now(); |
| }, 'Text with display style is observable.'); |
| </script> |
| </body> |
