html/meta/refresh-time.html

<!DOCTYPE html>
<meta charset="utf-8">
<title>Test fractional values in meta http-equiv=refresh</title>
<link rel="author" title="Psychpsyo"  href="mailto:psychpsyo@gmail.com">
<link rel="help" href="https://html.spec.whatwg.org/#pragma-directives">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>

<body>
<script>
  async function measureRefreshTime(src) {
    const frame = document.createElement("iframe");
    document.body.appendChild(frame);

    const loadPromise = new Promise(resolve => {
      frame.addEventListener("load", () => {
        resolve(performance.now());
      });
    });
    frame.src = src;
    const startTime = await loadPromise;

    const unloadPromise = new Promise(resolve => {
      frame.contentWindow.addEventListener("beforeunload", () => {
        resolve(performance.now());
      });
    });
    const endTime = await unloadPromise;
    return endTime - startTime;
  }

  promise_test(async test => {
    const refreshTime = await measureRefreshTime("resources/refresh1.html");
    assert_greater_than(refreshTime, 900);
  }, "Ensure that refresh is observed");

  promise_test(async test => {
    const refreshTime = await measureRefreshTime("resources/refresh1.99.html");
    assert_greater_than(refreshTime, 900);
  }, "Ensure that non-fractional part in refresh time does not get discarded");

  promise_test(async test => {
    const refreshTime = await measureRefreshTime("resources/refresh1dotdot9dot.html");
    assert_greater_than(refreshTime, 900);
  }, "Ensure that multiple periods in refresh time just get ignored");
</script>
</body>