chromium/third_party/blink/web_tests/http/tests/serviceworker/fetch-event-async-add.https.html

<!DOCTYPE html>
<title>Service Worker: Fetch event should not be handled when listener is added after script initial evaluation.</title>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="resources/test-helpers.js"></script>
<body>
<script>
// This test should not be upstreamed to WPT because it asserts that the event
// added after the initial evaluation of a worker script isn't fired. But
// this precision is not mandated by the current specifications.
promise_test(async function (t) {
  const scope = 'resources/simple.html?fetch-event-async-add';
  const script_url = 'resources/fetch-event-async-add-test-worker.js';

  t.add_cleanup(() => {
    frame.remove();
    return service_worker_unregister(t, scope);
  });

  const registration =
    await service_worker_unregister_and_register(t, script_url, scope);

  await wait_for_state(t, registration.installing, 'activated');
  const frame = await with_iframe(scope);

  assert_equals(frame.contentDocument.body.textContent,
                'Here\'s a simple html file.\n');
}, 'Service worker does not handle fetch event added after initial evaluation of worker script');

</script>
</body>