animation-restarted-after-changing-iteration-count-after-completion.html

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Setting 'animation-iteration-count: infinite' after a CSS Animation is completed restarts the animation</title>
<link rel="help" href="https://www.w3.org/TR/css-animations-1/#animation-iteration-count">
<style>

@keyframes anim {
    to { margin-left: 100px }
}

</style>
</head>
<body>
<script src=/resources/testharness.js></script>
<script src=/resources/testharnessreport.js></script>
<div id="target"></div>
<script>

promise_test(async test => {
    const target = document.getElementById("target");
    target.style.animation = "anim 0.1s linear";

    const initialAnimations = target.getAnimations();
    assert_equals(initialAnimations.length, 1, "An animation runs initially.");

    await initialAnimations[0].finished;
    assert_equals(target.getAnimations().length, 0, "An animation no longer runs after its completion.");

    await new Promise(setTimeout);
    target.style.animationIterationCount = "infinite";
    assert_equals(target.getAnimations().length, 1, "An animation runs again once animation-iteration-count is set.");
}, "Setting 'animation-iteration-count: infinite' after a CSS Animation is completed restarts the animation.");

</script>
</body>
</html>

chromium/third_party/blink/web_tests/external/wpt/css/css-animations/animation-restarted-after-changing-iteration-count-after-completion.html