chromium/third_party/blink/web_tests/external/wpt/service-workers/service-worker/update-result.https.html

<!DOCTYPE html>
<title>Service Worker: update() should resolve a ServiceWorkerRegistration</title>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="resources/test-helpers.sub.js"></script>
<body>
<script>

promise_test(async function(t) {
  const script = './resources/empty.js';
  const scope = './resources/empty.html?update-result';

  let reg = await navigator.serviceWorker.register(script, { scope });
  t.add_cleanup(async _ => await reg.unregister());
  await wait_for_state(t, reg.installing, 'activated');

  let result = await reg.update();
  assert_true(result instanceof ServiceWorkerRegistration,
              'update() should resolve a ServiceWorkerRegistration');
}, 'ServiceWorkerRegistration.update() should resolve a registration object');

</script>
</body>