chromium/third_party/blink/web_tests/external/wpt/service-workers/service-worker/postmessage-to-client.https.html

<!DOCTYPE html>
<title>Service Worker: postMessage to Client</title>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="/common/get-host-info.sub.js"></script>
<script src="resources/test-helpers.sub.js"></script>
<script>
promise_test(async t => {
  const script = 'resources/postmessage-to-client-worker.js';
  const scope = 'resources/blank.html';

  const registration =
      await service_worker_unregister_and_register(t, script, scope);
  t.add_cleanup(() => registration.unregister());
  await wait_for_state(t, registration.installing, 'activated');
  const frame = await with_iframe(scope);
  t.add_cleanup(() => frame.remove());
  const w = frame.contentWindow;

  w.navigator.serviceWorker.controller.postMessage('ping');
  let e = await new Promise(r => w.navigator.serviceWorker.onmessage = r);

  assert_equals(e.constructor, w.MessageEvent,
                'message events should use MessageEvent interface.');
  assert_equals(e.type, 'message', 'type should be "message".');
  assert_false(e.bubbles, 'message events should not bubble.');
  assert_false(e.cancelable, 'message events should not be cancelable.');
  assert_equals(e.origin, location.origin,
                'origin of message should be origin of Service Worker.');
  assert_equals(e.lastEventId, '',
                'lastEventId should be an empty string.');
  assert_equals(e.source.constructor, w.ServiceWorker,
                'source should use ServiceWorker interface.');
  assert_equals(e.source, w.navigator.serviceWorker.controller,
                'source should be the service worker that sent the message.');
  assert_equals(e.ports.length, 0, 'ports should be an empty array.');
  assert_equals(e.data, 'Sending message via clients');

  e = await new Promise(r => w.navigator.serviceWorker.onmessage = r);
  assert_equals(e.data, 'quit');
}, 'postMessage from ServiceWorker to Client.');
</script>