ad not having completed.
  await ensureWindowLoadEventFired(t);
  assert_equals(navigation.entries().length, start_length);


  let navigateEventType;
  navigation.onnavigate = e => {
    navigateEventType = e.navigationType;
    e.intercept();
  }
  navigation.onnavigateerror = t.unreached_func("onnavigateerror should not be called");

  await navigation.navigate(location.href, { history: "push" }).finished;
  assert_equals(navigateEventType, "push");
  assert_equals(navigation.entries().length, start_leng