private void Given_That_A_TestMessageHandler_Has_Been_Registered()
 {
     _testMessageHandler = Substitute.For<IHandle>();
     _testMessageHandler.MessageType.Returns(typeof(TestMessage));
     _messageBus = new SimpleMessageBus(new [] {_testMessageHandler});
 }
 private void Given_That_No_Handlers_Have_Been_Registered()
 {
     _messageBus = new SimpleMessageBus(null);
 }