web-animations/responsive/shapeMargin.html

<!DOCTYPE html>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>

<div id='container'>
<div id='element'></div>
</div>

<script>
var element = document.getElementById('element');
var container = document.getElementById('container');

test(function() {
    element.style.fontSize = '10px';
    element.style.width = '200px';
    var player = element.animate([{shapeMargin: '3em'}, {shapeMargin: '80%'}], 10);
    player.pause();
    player.currentTime = 5;
    element.style.fontSize = '20px';
    element.style.width = '100px';
    assert_equals(getComputedStyle(element).shapeMargin, 'calc(40% + 30px)');
}, 'shapeMargin responsive to style changes');

</script>