mozilla-release/testing/web-platform/tests/cookie-store/serviceworker_cookieStore_basic.tentative.https.html

<!doctype html>
<meta charset="utf-8">
<title>Async Cookies: cookieStore basic API in ServiceWorker</title>
<link rel="help" href="https://github.com/WICG/cookie-store">
<link rel="author" href="pwnall@chromium.org" title="Victor Costan">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script>
'use strict';

(async () => {
  const scope = 'does/not/exist';

  let registration = await navigator.serviceWorker.getRegistration(scope);
  if (registration)
    await registration.unregister();
  registration = await navigator.serviceWorker.register(
      'serviceworker_cookieStore_basic.js', {scope});

  fetch_tests_from_worker(registration.installing);
})();
</script>