@VisibleForTesting
  void notifyTokenExpiration() {
    try {
      // Avoid notification multiple times in case of data center edition
      if (!lockManager.tryLock(LOCK_NAME, LOCK_DURATION)) {
        return;
      }
      notificationSender.sendNotifications();
    } catch (RuntimeException e) {
      LOG.error("Error in sending token expiration notification", e);
    }
  }
@Test
  public void no_notification_if_it_is_already_sent() {
    when(lockManager.tryLock(anyString(), anyInt())).thenReturn(false);
    underTest.notifyTokenExpiration();
    verifyNoInteractions(notificationSender);
  }