<body>
<style>
    
    body {
        background-color: green;
    }
    
    div {
        position: absolute;
        top: 0;
        left: 0;
        width: 100px;
        height: 100px;
        background-color: red;
    }

    /* Allow for a 1px error on either side */
    #easing-on-keyframe {
        left: -1px;
        width: 102px;
        background-color: green;
    }

</style>
<div id="easing-on-animation-one-keyframe"></div>
<div id="easing-on-animation-two-keyframes"></div>
<div id="easing-on-animation-three-keyframes"></div>
<div id="easing-on-keyframe"></div>
<script>

(async function() {
    if (window.testRunner)
        testRunner.waitUntilDone();

    const animations = [];

    animations.push(document.getElementById("easing-on-animation-one-keyframe").animate({ transform: "translateX(100px)" }, {
        duration: 500,
        easing: "ease",
        direction: "alternate",
        iterations: Infinity
    }));

    animations.push(document.getElementById("easing-on-animation-two-keyframes").animate([
        { transform: "translateX(0)" },
        { transform: "translateX(100px)" }
    ], {
        duration: 500,
        easing: "ease",
        direction: "alternate",
        iterations: Infinity
    }));

    animations.push(document.getElementById("easing-on-animation-three-keyframes").animate([
        { transform: "translateX(0)" },
        { transform: "translateX(50px)" },
        { transform: "translateX(100px)" }
    ], {
        duration: 500,
        easing: "ease",
        direction: "alternate",
        iterations: Infinity
    }));

    animations.push(document.getElementById("easing-on-keyframe").animate([
        { transform: "translateX(0)", easing: "ease" },
        { transform: "translateX(100px)" }
    ], {
        duration: 500,
        direction: "alternate",
        iterations: Infinity
    }));

    await Promise.all(animations.map(animation => animation.ready));
    await new Promise(requestAnimationFrame);
    await new Promise(requestAnimationFrame);
    await new Promise(requestAnimationFrame);

    if (window.testRunner)
        testRunner.notifyDone();
})();

</script>
</body>