servo/tests/wpt/web-platform-tests/web-animations/timing-model/timelines/document-timelines.html

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HTML

<!doctype html>
<meta charset=utf-8>
<title>Document timelines</title>
<link rel="help" href="https://drafts.csswg.org/web-animations/#document-timelines">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="../../testcommon.js"></script>
<div id="log"></div>
<script>
'use strict';
async_test(t => {
assert_true(document.timeline.currentTime > 0,
'The current time is initially is positive');
// document.timeline.currentTime should be set even before document
// load fires. We expect this code to be run before document load and hence
// the above assertion is sufficient.
// If the following assertion fails, this test needs to be redesigned.
assert_true(document.readyState !== 'complete',
'Test is running prior to document load');
// Test that the document timeline's current time is measured from
// navigationStart.
//
// We can't just compare document.timeline.currentTime to
// window.performance.now() because currentTime is only updated on a sample
// so we use requestAnimationFrame instead.
window.requestAnimationFrame(rafTime => {
t.step(() => {
assert_equals(document.timeline.currentTime, rafTime,
'The current time matches requestAnimationFrame time');
});
t.done();
});
}, 'Document timelines report current time relative to navigationStart');
</script>