<!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_greater_than_equal(document.timeline.currentTime, 0,
    'The current time is initially is positive or zero');

  // 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_not_equals(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');

async_test(t => {
  window.requestAnimationFrame(rafTime => {
    t.step(() => {
      const iframe = document.createElement('iframe');
      document.body.appendChild(iframe);
      assert_greater_than_equal(iframe.contentDocument.timeline.currentTime, 0,
        'The current time of a new iframe is initially is positive or zero');
    });
    t.done();
  });
}, 'Child frames do not report negative initial times');

</script>