public void Should_dispatch_message_to_registered_handler()
{
const string messageType = "messageType";
IMessageHandler messageHandler = CreateHandler(messageType);
IMessage message = CreateMessage(messageType);
_subject.Register(messageHandler);
_subject.Dispatch(message);
messageHandler.AssertWasCalled(h => h.Handle(message));
_defaultHandler.AssertWasNotCalled(h => h.Handle(Arg <IMessage> .Is.Anything));
}