chromium/third_party/blink/web_tests/animations/width-using-ems.html

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
   "http://www.w3.org/TR/html4/loose.dtd">

<html lang="en">
<head>
  <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
  <title>Test of width Animation Using em Units</title>
  <style type="text/css" media="screen">
    body {
        font-family: "arial";
        font-size: 10px;
    }

    #box {
        position: absolute;
        left: 0;
        top: 100px;
        height: 100px;
        width: 100px;
        border: 1px solid black;
        animation-duration: 10s;
        animation-timing-function: linear;
        animation-name: anim;
    }
    @keyframes anim {
        from { width: 10em; }
        to   { width: 110em; }
    }
    </style>
    <script src="resources/animation-test-helpers.js" type="text/javascript" charset="utf-8"></script>
    <script type="text/javascript" charset="utf-8">

    const expectedValues = [
      // [time, element-id, property, expected-value, tolerance]
      [0.333, "box", "width", 133, 1],
    ];

    runAnimationTest(expectedValues);

  </script>
</head>
<body>
This test performs an animation of the width property using 'em' units. It tests whether or not we are properly
getting the default font-size.
<div id="box">
Here is some text. Here is some text. Here is some text. Here is some text. Here is some text. Here is some text.
</div>
<div id="result">
</div>
</body>
</html>