/**
   * Waits for the {@link ServiceManager} to become {@linkplain #isHealthy() healthy}. The manager
   * will become healthy after all the component services have reached the {@linkplain State#RUNNING
   * running} state.
   *
   * @throws IllegalStateException if the service manager reaches a state from which it cannot
   *     become {@linkplain #isHealthy() healthy}.
   */
  public void awaitHealthy() {
    state.awaitHealthy();

   * This is for covering a case where the ServiceManager would behave strangely if constructed with
   * no service under management. Listeners would never fire because the ServiceManager was healthy
   * and stopped at the same time. This test ensures that listeners fire and isHealthy makes sense.
   */
  public void testEmptyServiceManager() {
    Logger logger = Logger.getLogger(ServiceManager.class.getName());
    logger.setLevel(Level.FINEST);

   * This is for covering a case where the ServiceManager would behave strangely if constructed with
   * no service under management. Listeners would never fire because the ServiceManager was healthy
   * and stopped at the same time. This test ensures that listeners fire and isHealthy makes sense.
   */
  public void testEmptyServiceManager() {
    Logger logger = Logger.getLogger(ServiceManager.class.getName());
    logger.setLevel(Level.FINEST);