public void RegisterSameVerbDifferentCase() { MessageBus bus = new MessageBus(); List <string> output = new List <string>(); Action <OutputMessage> subscriber = m => output.Add(m.Text); bus.Subscribe(subscriber); TestRoom room = new TestRoom(bus); room.Enter(); Action act = () => room.TestRegisterHello("HeLLO"); act.Should().Throw <InvalidOperationException>().WithMessage("The verb 'HeLLO' is already registered."); }