chromium/third_party/blink/web_tests/svg/animations/updated-attributes.html

<html>
<body>
  <!-- Test for https://bugs.webkit.org/show_bug.cgi?id=93972 -->
  <div id="result"></div>

  <svg xmlns="http://www.w3.org/2000/svg">
    <rect id="rect" height="100" fill="green">
      <animate id="animation" attributeName="width" from="10" to="100" begin="0s" dur="indefinite" fill="freeze" />
    </rect>
  </svg>

<script>
  if (window.testRunner) {
    testRunner.dumpAsText();
    testRunner.waitUntilDone();
  }

  function check() {
    var width = document.getElementById('rect').width.animVal.value;
    document.getElementById('result').innerHTML = (width == 100 ? "PASS: " : "FAIL: ") + 'animated width is ' + width;

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

  window.setTimeout(function() {
    var ani = document.getElementById('animation');
    ani.setAttribute("from", "100");
    ani.beginElement();

    window.setTimeout(function() { check(); }, 0);
  }, 0);
</script>
</body>
</html>