animation-worklet/worklet-animation-with-fill-mode.https.html

<!DOCTYPE html>
<title>Test that worklet animation works with different fill modes</title>
<link rel="help" href="https://drafts.css-houdini.org/css-animationworklet/">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="/web-animations/testcommon.js"></script>
<script src="common.js"></script>

<style>
.target {
  width: 100px;
  height: 100px;
  background-color: green;
}
</style>

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

<script>
setup(setupAndRegisterTests, {explicit_done: true});

function setupAndRegisterTests() {
  registerConstantLocalTimeAnimator(2000).then(() => {
    promise_test(
        effect_with_fill_mode_forwards,
        "Effect with fill mode forwards in after phase produces output that is equivalent to effect's end value.");

    promise_test(
        effect_without_fill_mode_forwards,
        'Effect without fill mode forwards in after phase (local time beyond end) should deactivate the animation.');

    promise_test(
        effect_without_fill_forwards_at_end,
        'Effect without fill mode in after phase (local time at end) should deactivate the animation.');

    promise_test(
        effect_with_fill_backwards,
        "Effect with fill mode backwards in before phase produces output that is equivalent to effect's start value.");

    promise_test(
        effect_without_fill_backwards,
        'Effect without fill mode backwards in before phase (local time before start) should deactivate the animation.');

    promise_test(
        effect_without_fill_backwards_at_start,
        'Effect with local time at start point is in active phase.');

    done();
  });
}

async function effect_with_fill_mode_forwards(t) {
  const effect_with_fill_forwards = new KeyframeEffect(
      target,
      { opacity: [0.5, 0] },
      { duration: 1000, fill: 'forwards' });
  const animation = new WorkletAnimation(
      'constant_time',
      effect_with_fill_forwards);
  animation.play();
  await waitForNotNullLocalTime(animation);

  assert_equals(getComputedStyle(target).opacity, '0');

  animation.cancel();
}

async function effect_without_fill_mode_forwards(t) {
  const effect_without_fill_forwards = new KeyframeEffect(
      target,
      { opacity: [0.5, 0] },
      { duration: 1000 });
  const animation = new WorkletAnimation(
      'constant_time',
      effect_without_fill_forwards);
  animation.play();
  await waitForNotNullLocalTime(animation);

  assert_equals(getComputedStyle(target).opacity, '1');

  animation.cancel();
}

async function effect_without_fill_forwards_at_end(t) {
  const effect_without_fill_forwards_at_end = new KeyframeEffect(
      target,
      { opacity: [0.5, 0] },
      { duration: 2000 });
  const animation = new WorkletAnimation(
      'constant_time',
      effect_without_fill_forwards_at_end);
  animation.play();
  await waitForNotNullLocalTime(animation);

  assert_equals(getComputedStyle(target).opacity, '1');

  animation.cancel();
}

async function effect_with_fill_backwards(t) {
  const effect_with_fill_backwards = new KeyframeEffect(
      target,
      { opacity: [0.5, 0] },
      { duration: 1000, delay: 2001, fill: 'backwards' });
  const animation = new WorkletAnimation(
      'constant_time',
      effect_with_fill_backwards);
  animation.play();
  await waitForNotNullLocalTime(animation);

  assert_equals(getComputedStyle(target).opacity, '0.5');

  animation.cancel();
}

async function effect_without_fill_backwards(t) {
  const effect_without_fill_backwards = new KeyframeEffect(
      target,
      { opacity: [0.5, 0] },
      { duration: 1000, delay: 2001 });
  const animation = new WorkletAnimation(
      'constant_time',
      effect_without_fill_backwards);
  animation.play();
  waitForNotNullLocalTime(animation);

  assert_equals(getComputedStyle(target).opacity, '1');

  animation.cancel();
}

async function effect_without_fill_backwards_at_start(t) {
  const effect_without_fill_backwards_at_start = new KeyframeEffect(
      target,
      { opacity: [0.5, 0] },
      { duration: 1000, delay: 2000 });
  const animation = new WorkletAnimation(
      'constant_time',
      effect_without_fill_backwards_at_start);
  animation.play();
  await waitForNotNullLocalTime(animation);

  assert_equals(getComputedStyle(target).opacity, '0.5');

  animation.cancel();
}
</script>