<style>
    #foo {
        animation-name: rule1;
    }
    @keyframes rule1 { }
    @keyframes rule2 { }
</style>
<div id="foo"></div>
<script src="../include.js"></script>
<script>
    asyncTest(done => {
        const foo = document.getElementById("foo");
        println(`before: ${getComputedStyle(foo).getPropertyValue("animation-name")}`);
        foo.style.setProperty("animation-name", "rule2");
        requestAnimationFrame(() => {
            println(`after: ${getComputedStyle(foo).getPropertyValue("animation-name")}`);
            done();
        });
    });
</script>