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