css/css-animations/CSSAnimation-pausing.tentative.html

<!doctype html>
<meta charset=utf-8>
<title>Pausing a CSSAnimation</title>
<link rel="help"
      href="https://drafts.csswg.org/css-animations-2/#animation-play-state">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="support/testcommon.js"></script>
<style>
@keyframes anim {
  0% { margin-left: 0px }
  100% { margin-left: 10000px }
}
</style>
<div id="log"></div>
<script>
'use strict';

const getMarginLeft = cs => parseFloat(cs.marginLeft);

promise_test(async t => {
  const div = addDiv(t);
  const cs = getComputedStyle(div);
  div.style.animation = 'anim 1000s paused';
  const animation = div.getAnimations()[0];
  assert_equals(getMarginLeft(cs), 0,
                'Initial value of margin-left is zero');
  animation.play();

  await animation.ready;
  await waitForNextFrame();

  assert_greater_than(getMarginLeft(cs), 0,
                      'Playing value of margin-left is greater than zero');
}, 'play() overrides animation-play-state');

promise_test(async t => {
  const div = addDiv(t);
  const cs = getComputedStyle(div);
  div.style.animation = 'anim 1000s paused';
  const animation = div.getAnimations()[0];
  assert_equals(getMarginLeft(cs), 0,
                'Initial value of margin-left is zero');

  animation.pause();
  div.style.animationPlayState = 'running';

  await animation.ready;
  await waitForNextFrame();

  assert_equals(cs.animationPlayState, 'running',
                'animation-play-state is running');
  assert_equals(getMarginLeft(cs), 0,
                'Paused value of margin-left is zero');
}, 'pause() overrides animation-play-state');

promise_test(async t => {
  const div = addDiv(t);
  const cs = getComputedStyle(div);
  div.style.animation = 'anim 1000s paused';
  const animation = div.getAnimations()[0];
  assert_equals(getMarginLeft(cs), 0,
                'Initial value of margin-left is zero');
  animation.play();

  await animation.ready;

  div.style.animationPlayState = 'running';
  cs.animationPlayState; // Trigger style resolution
  await waitForNextFrame();

  assert_equals(cs.animationPlayState, 'running',
                'animation-play-state is running');
  div.style.animationPlayState = 'paused';
  await animation.ready;

  assert_equals(cs.animationPlayState, 'paused',
                'animation-play-state is paused');
  const previousAnimVal = getMarginLeft(cs);
  await waitForNextFrame();

  assert_equals(getMarginLeft(cs), previousAnimVal,
                'Animated value of margin-left does not change when'
                + ' paused by style');
}, 'play() is overridden by later setting "animation-play-state: paused"');

promise_test(async t => {
  const div = addDiv(t);
  const cs = getComputedStyle(div);
  div.style.animation = 'anim 1000s';
  const animation = div.getAnimations()[0];
  assert_equals(getMarginLeft(cs), 0,
                'Initial value of margin-left is zero');

  // Set the specified style first. If implementations fail to
  // apply the style changes first, they will ignore the redundant
  // call to play() and fail to correctly override the pause style.
  div.style.animationPlayState = 'paused';
  animation.play();
  const previousAnimVal = getMarginLeft(cs);

  await animation.ready;
  await waitForNextFrame();

  assert_equals(cs.animationPlayState, 'paused',
                'animation-play-state is paused');
  assert_greater_than(getMarginLeft(cs), previousAnimVal,
                      'Playing value of margin-left is increasing');
}, 'play() flushes pending changes to animation-play-state first');

promise_test(async t => {
  const div = addDiv(t);
  const cs = getComputedStyle(div);
  div.style.animation = 'anim 1000s paused';
  const animation = div.getAnimations()[0];
  assert_equals(getMarginLeft(cs), 0,
                'Initial value of margin-left is zero');

  // Unlike the previous test for play(), since calling pause() is sticky,
  // we'll apply it even if the underlying style also says we're paused.
  //
  // We would like to test that implementations flush styles before running
  // pause() but actually there's no style we can currently set that will
  // change the behavior of pause(). That may change in the future
  // (e.g. if we introduce animation-timeline or animation-playback-rate etc.).
  //
  // For now this just serves as a sanity check that we do the same thing
  // even if we set style before calling the API.
  div.style.animationPlayState = 'running';
  animation.pause();
  const previousAnimVal = getMarginLeft(cs);

  await animation.ready;
  await waitForNextFrame();

  assert_equals(cs.animationPlayState, 'running',
                'animation-play-state is running');
  assert_equals(getMarginLeft(cs), previousAnimVal,
                'Paused value of margin-left does not change');
}, 'pause() applies pending changes to animation-play-state first');
// (Note that we can't actually test for this; see comment above, in test-body.)

promise_test(async t => {
  const div = addDiv(t, { style: 'animation: anim 1000s' });
  const animation = div.getAnimations()[0];
  let readyPromiseRun = false;

  await animation.ready;

  div.style.animationPlayState = 'paused';
  assert_true(animation.pending && animation.playState === 'paused',
              'Animation is pause-pending');

  // Set current time
  animation.currentTime = 5 * MS_PER_SEC;
  assert_equals(animation.playState, 'paused',
                'Animation is paused immediately after setting currentTime');
  assert_equals(animation.startTime, null,
                'Animation startTime is unresolved immediately after ' +
                'setting currentTime');
  assert_equals(animation.currentTime, 5 * MS_PER_SEC,
                'Animation currentTime does not change when forcing a ' +
                'pause operation to complete');

  // The ready promise should now be resolved. If it's not then test will
  // probably time out before anything else happens that causes it to resolve.
  await animation.ready;
}, 'Setting the current time completes a pending pause');

</script>