52 lines
2.1 KiB
HTML
52 lines
2.1 KiB
HTML
<!DOCTYPE HTML>
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<meta charset=utf-8>
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<title>Largest Contentful Paint: observe text.</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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p {
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font-size: 12px;
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}
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</style>
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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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const observer = new PerformanceObserver(
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t.step_func_done(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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// PaintTimingMixin
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assert_greater_than_equal(entry.paintTime, beforeRender, 'paintTime should represent the time when the UA started painting');
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if ("presentationTime" in entry && entry.presentationTime !== null) {
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assert_greater_than(entry.presentationTime, entry.paintTime);
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assert_equals(entry.presentationTime, entry.renderTime);
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} else {
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assert_equals(entry.renderTime, entry.paintTime);
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}
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assert_equals(entry.duration, 0);
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// Some lower bound: height of at least 12 px.
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// Width of at least 100 px.
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// TODO: find a good way to bound text width.
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assert_greater_than_equal(entry.size, 1200);
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assert_equals(entry.loadTime, 0);
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assert_equals(entry.id, 'my_text');
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assert_equals(entry.url, '');
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assert_equals(entry.element, document.getElementById('my_text'));
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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 element is observable as a LargestContentfulPaint candidate.');
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</script>
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<p id='my_text'>This is important text! :)</p>
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</body>
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