### Question:
ActorManager { Mono<Void> invokeTimer(ActorId actorId, String timerName) { return Mono.fromSupplier(() -> { AbstractActor actor = this.activeActors.getOrDefault(actorId, null); if (actor == null) { throw new IllegalArgumentException( String.format("Could not find actor %s of type %s.", actorId.toString(), this.runtimeContext.getActorTypeInformation().getName())); } ActorTimer actorTimer = actor.getActorTimer(timerName); if (actorTimer == null) { throw new IllegalStateException( String.format("Could not find timer %s for actor %s.", timerName, this.runtimeContext.getActorTypeInformation().getName())); } return actorTimer; }).flatMap(actorTimer -> invokeMethod( actorId, ActorMethodContext.createForTimer(actorTimer.getName()), actorTimer.getCallback(), actorTimer.getState())) .then(); } ActorManager(ActorRuntimeContext runtimeContext);   }### Answer:
@Test(expected = IllegalArgumentException.class) public void invokeTimerBeforeActivate() { ActorId actorId = newActorId(); this.manager.invokeTimer(actorId, "count").block(); }