LayoutTests/webanimations/scheduling-of-animation-without-keyframes.html

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

const noKeyframesTest = (keyframes, label) => {
    promise_test(async () => {
        const animation = document.querySelector("div").animate(keyframes, 1000);
        await animation.ready;
        animation.currentTime = 100;
        assert_equals(internals.timeToNextAnimationTick(animation), 900);
    }, `Computing the time until the next tick for an effect with ${label} keyframes parameter.`);
}

noKeyframesTest(null, "null");
noKeyframesTest({}, "{}");
noKeyframesTest([], "[]");
noKeyframesTest({ foo: "bar" }, "invalid CSS property");

</script>