chromium/third_party/blink/web_tests/external/wpt/service-workers/service-worker/controller-on-reload.https.html

<!DOCTYPE html>
<title>Service Worker: Controller on reload</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(function(t) {
    const iframe_scope = 'blank.html';
    const scope = 'resources/' + iframe_scope;
    var frame;
    var registration;
    var controller;
    return service_worker_unregister(t, scope)
      .then(function() {
          t.add_cleanup(function() {
              return service_worker_unregister(t, scope);
            });

          return with_iframe(scope);
        })
      .then(function(f) {
          frame = f;
          return frame.contentWindow.navigator.serviceWorker.register(
              'empty-worker.js', {scope: iframe_scope});
        })
      .then(function(swr) {
          registration = swr;
          return wait_for_state(t, registration.installing, 'activated');
        })
      .then(function() {
          var w = frame.contentWindow;
          assert_equals(w.navigator.serviceWorker.controller, null,
                        'controller should be null until the document is ' +
                        'reloaded');
          return new Promise(function(resolve) {
              frame.onload = function() { resolve(); }
              w.location.reload();
            });
        })
      .then(function() {
          var w = frame.contentWindow;
          controller = w.navigator.serviceWorker.controller;
          assert_true(controller instanceof w.ServiceWorker,
                      'controller should be a ServiceWorker object upon reload');

          // objects from separate windows should not be equal
          assert_not_equals(controller, registration.active);

          return w.navigator.serviceWorker.getRegistration(iframe_scope);
        })
      .then(function(frameRegistration) {
          assert_equals(frameRegistration.active, controller);
          frame.remove();
        });
  }, 'controller is set upon reload after registration');
</script>
</body>