chromium/third_party/blink/web_tests/external/wpt/css/css-animations/pending-style-changes-001.html

<meta charset=utf-8>
<title>CSS Animations Test: requirement on pending style changes - getAnimations</title>
<link rel="help" href="https://drafts.csswg.org/css-animations-2/#requirements-on-pending-style-changes">

<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>

<style>
@keyframes anim {}

.animate {
  animation: anim 10s;
}
</style>

<div id="target"></div>

<script>
test (t => {
  assert_equals(target.getAnimations().length, 0, 'Test precondition.');
  target.classList.add('animate');
  assert_equals(target.getAnimations().length, 1,
      'target.getAnimations() should include the CSS animation after animate class added.');
  target.classList.remove('animate');
}, 'Animatable::getAnimations() should be able to see a style-created CSS animation immediately');

test(t => {
  assert_equals(document.getAnimations().length, 0, 'Test precondition.');
  target.classList.add('animate');
  assert_equals(document.getAnimations().length, 1,
     'document.getAnimations() should include the CSS animation after animate class added.');
  target.classList.remove('animate');
}, 'Document::getAnimations() should be able to see a style-created CSS animation immediately');
</script>