<html>
<style>
div {
    position: relative;
    height: 100px;
    width: 100px;
    background: blue;
    transform: translateZ(0);
    animation-direction: alternate;
    animation-duration: 2s;
    animation-timing-function: linear;
    animation-fill-mode: both;
}

.test0 {
    animation-iteration-count: 0;
}

.test1 {
     animation-iteration-count: 0.5;
}

.test2 {
    animation-iteration-count: 1;
}

.test3 {
    animation-iteration-count: 1.5;
}

.test4 {
    animation-iteration-count: 2;
}

.test5 {
    animation-iteration-count: 2.5;
}

.anim-left {
    animation-name: anim-left;
    z-index: 100;
}

.anim-transform {
    animation-name: anim-transform;
    z-index: 200;
}

@keyframes anim-left {
    0% {
        left: 0px;
    }
    100% {
        left: 300px;
    }
}

@keyframes anim-transform {
    0% {
        transform: translateX(0px);
    }
    100% {
        transform: translateX(300px);
    }
}
</style>
<body>
<p>
Each section below has two boxes, the top runs on the main thread, the bottom
on the compositor. The animations should be identical but start at different
times.
</p><p>
This test is successful if the boxes are mostly in sync (there might be a small
offset between them).
</p>
<hr>

Iteration count 0 (should not animate)
<br>
<div class='test0 anim-left'></div>
<div class='test0 anim-transform'></div>

Iteration count 0.5 (should finish first in the middle)
<br>
<div class='test1 anim-left'></div>
<div class='test1 anim-transform'></div>

Iteration count 1 (should finish second at the end)
<br>
<div class='test2 anim-left'></div>
<div class='test2 anim-transform'></div>

Iteration count 1.5 (should finish third in the middle)
<br>
<div class='test3 anim-left'></div>
<div class='test3 anim-transform'></div>

Iteration count 2 (should finish fourth at the start)
<br>
<div class='test4 anim-left'></div>
<div class='test4 anim-transform'></div>

Iteration count 2.5 (should finish last in the middle)
<br>
<div class='test5 anim-left'></div>
<div class='test5 anim-transform'></div>
</body>
</html>