LayoutTests/webanimations/scheduling-of-animation-with-steps-timing-function-on-keyframe.html

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

promise_test(async t => {
    const animation = document.querySelector("div").animate({
        marginLeft: ["0", "250px", "500px", "750px", "1000px"],
        easing: ["linear", "linear", "steps(10)", "linear"]
    }, 1000);

    await animation.ready;

    animation.currentTime = 535;
    assert_equals(internals.timeToNextAnimationTick(animation), 15);
}, "Computing the time until the next tick for a keyframe with a steps() timing function.");

</script>