fetch/stale-while-revalidate/fetch-sw.https.html

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <title>Stale Revalidation Requests don't get sent to service worker</title>
  <script src="/resources/testharness.js"></script>
  <script src="/resources/testharnessreport.js"></script>
  <script src="../../service-workers/service-worker/resources/test-helpers.sub.js"></script>
  <script src="/common/utils.js"></script>
</head>
<body>
<script>

  // Duplicating this resource to make service worker scoping simpler.
  async function setupRegistrationAndWaitToBeControlled(t, scope) {
    const controlled = new Promise((resolve) => {
      navigator.serviceWorker.oncontrollerchange = () => { resolve(); };
    });
    const reg = await navigator.serviceWorker.register('sw-intercept.js');
    await wait_for_state(t, reg.installing, 'activated');
    await controlled;
    add_completion_callback(_ => reg.unregister());
    return reg;
  }

  // Using 250ms polling interval to provide enough 'network calmness' to give
  // the background low priority revalidation request a chance to kick in.
  function wait250ms(test) {
    return new Promise(resolve => {
      test.step_timeout(() => {
        resolve();
      }, 250);
    });
  }

  promise_test(async (test) => {
    var request_token = token();
    const uri = 'resources/stale-script.py?token=' + request_token;

    await setupRegistrationAndWaitToBeControlled(test, 'resources/stale-script.py');

    var service_worker_count = 0;
    navigator.serviceWorker.addEventListener('message', function once(event) {
      if (event.data.endsWith(uri)) {
        service_worker_count++;
      }
    });

    const response = await fetch(uri);
    const response2 = await fetch(uri);
    assert_equals(response.headers.get('Unique-Id'), response2.headers.get('Unique-Id'));
    while(true) {
      const revalidation_check = await fetch(`resources/stale-script.py?query&token=` + request_token);
      if (revalidation_check.headers.get('Count') == '2') {
        // The service worker should not see the revalidation request.
        assert_equals(service_worker_count, 2);
        break;
      }
      await wait250ms(test);
    }
  }, 'Second fetch returns same response');

</script>
</body>
</html>