private static final ListenerCallQueue.Event<Listener> HEALTHY_EVENT =
      new ListenerCallQueue.Event<Listener>() {
        @Override
        public void call(Listener listener) {
          listener.healthy();
        }

        @Override
        public String toString() {
          return "healthy()";
        }
      };

    assertThrows(IllegalStateException.class, () -> manager.startAsync().awaitHealthy());
    assertTrue(listener.stoppedCalled);
  }

  /**
   * This covers a bug where listener.healthy would get called when a single service failed during
   * startup (it occurred in more complicated cases also).
   */
  public void testFailStart_singleServiceCallsHealthy() {
    Service a = new FailStartService();

    assertThrows(IllegalStateException.class, () -> manager.startAsync().awaitHealthy());
    assertTrue(listener.stoppedCalled);
  }

  /**
   * This covers a bug where listener.healthy would get called when a single service failed during
   * startup (it occurred in more complicated cases also).
   */
  public void testFailStart_singleServiceCallsHealthy() {
    Service a = new FailStartService();