first-interval-in-the-past-dont-contribute.html

<!DOCTYPE html>
<title>Animation element that end before time container begin</title>
<link rel="help" href="https://www.w3.org/TR/2001/REC-smil-animation-20010904/#Timing-BeginEnd-LC-Start">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="/common/rendering-utils.js"></script>
<svg>
  <rect width="100" height="100" fill="green">
    <animate attributeName="fill" values="red;red" begin="-1s" dur="1s" fill="freeze"/>
  </rect>
  <set attributeName="stroke-width" to="10"/>
</svg>
<script>
  promise_test(t => {
    const animationStart = new Promise(resolve => {
      document.querySelector('set').onbegin = resolve;
    });
    return animationStart
      .then(() =>
        waitForAtLeastOneFrame())
      .then(() => {
        const rect = document.querySelector('rect');
        assert_equals(getComputedStyle(rect).fill, 'rgb(0, 128, 0)', 'animation does not apply');
      });
  });
</script>

chromium/third_party/blink/web_tests/external/wpt/svg/animations/first-interval-in-the-past-dont-contribute.html