@Test(expected = OmegaException.class)
public void participateFailedThenAbort() {

  TccMessageSender failedSender = mock(GrpcTccClientMessageSender.class);
  doThrow(new OmegaException("omega exception")).when(failedSender).participationStart((ParticipationStartedEvent)any());
  TccMessageSender succeedSender = mock(GrpcTccClientMessageSender.class);
  when(succeedSender.participationStart((ParticipationStartedEvent) any())).thenReturn(new AlphaResponse(false));
  Map<MessageSender, Long> senders = Maps.newConcurrentMap();
  senders.put(failedSender, 0l);
  senders.put(succeedSender, 10l);
  loadContext.setSenders(senders);
  tccLoadBalanceSender.participationStart(participationStartedEvent);
}