animation-worklet/worklet-animation-without-target.https.html

<!DOCTYPE html>
<title>Verify that effect without target is supported</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>

<div id="box"></div>

<script>

setup(setupAndRegisterTests, {explicit_done: true});

async function setupAndRegisterTests() {
  await registerPassthroughAnimator();

  promise_test(async t => {
    const effect = new KeyframeEffect(null,
      { transform: ['translateY(100px)', 'translateY(200px)'] },
      { duration: Infinity, iterations: 1 }
    );
    const animation = new WorkletAnimation('passthrough', effect);
    animation.play();

    // Allow one async animation frame to pass so that animation is running.
    await waitForAsyncAnimationFrames(1);
    assert_equals(animation.playState, "running");
    // Allow time to advance so that we have a non-zero current time.
    await waitForDocumentTimelineAdvance();
    const t0 = document.timeline.currentTime;
    assert_greater_than(animation.currentTime, 0);
    assert_times_equal(animation.currentTime, (t0 - animation.startTime));
    assert_equals(animation.playState, "running");

    animation.cancel();
  }, 'Animating effect with no target should work.');

  promise_test(async t => {
    const effect = new KeyframeEffect(document.getElementById('box'),
      { transform: ['translateY(100px)', 'translateY(200px)'] },
      { duration: Infinity, iterations: 1 }
    );

    const animation = new WorkletAnimation('passthrough', effect);
    animation.play();

    // Allow one async animation frame to pass so that animation is running.
    await waitForAsyncAnimationFrames(1);
    assert_equals(animation.playState, "running");
    // Allow time to advance so that we have a non-zero current time.
    await waitForDocumentTimelineAdvance();
    const t0 = document.timeline.currentTime;
    assert_greater_than(animation.currentTime, 0);
    assert_times_equal(animation.currentTime, (t0 - animation.startTime));
    assert_equals(animation.playState, "running");

    await waitForDocumentTimelineAdvance();
    animation.effect.target = null;
    const t1 = document.timeline.currentTime;
    assert_times_equal(animation.currentTime, (t1 - animation.startTime));
    assert_equals(animation.playState, "running");

    await waitForDocumentTimelineAdvance();
    animation.effect.target = document.getElementById('box');
    const t2 = document.timeline.currentTime;
    assert_times_equal(animation.currentTime, (t2 - animation.startTime));
    assert_equals(animation.playState, "running");

    animation.cancel();
  }, 'The existence of a target does not affect the animation.');

  done();
}
</script>