<!DOCTYPE html>
<link rel="author" href="mailto:graouts@apple.com">
<link rel="help" href="https://drafts.csswg.org/css-animations/">
<link rel="help" href="https://drafts.csswg.org/selectors/#the-empty-pseudo">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="/css/css-animations/support/testcommon.js"></script>

<div class="container"></div>

<style>

.container {
  width: 100px;
  height: 100px;
  background-color: rgb(0, 255, 0);
}

.container:empty {
  background-color: rgb(255, 0, 0);
  animation: anim 1s;
}

@keyframes anim { }

</style>

<script>

promise_test(async () => {
  const container = document.querySelector(".container");
  const computedStyle = getComputedStyle(container);

  // Check that the :empty rule applies initially.
  assert_equals(computedStyle.backgroundColor, 'rgb(255, 0, 0)',
    'The initial background-color matches the value set by the :empty rule.');

  // Await a couple of frames to let any animation-related style updates happen.
  await waitForAnimationFrames(2);

  // Append a child which should no longer let the :empty rule apply.
  container.appendChild(document.createElement("span"));
  assert_equals(computedStyle.backgroundColor, 'rgb(0, 255, 0)',
    'The background-color after inserting a child into the container no longer matches the value set by the :empty rule.');
}, 'Setting an "animation" style property on an element does not interfere with the :empty pseudo-class.');

</script>