bug in nsb tests

gistfile1.cs

        [Test]
        public void TestMessageCast()
        {
            var id = Guid.NewGuid();
            nsTest.Initialize();
            nsTest.Handler<CommandHandler>()
                .ExpectSend<CreateBookingCommand>(m => m.ShipmentId == id)
                .ExpectSend<CreatedShipmentEvent>(m => m.ShipmentId == id)
                .OnMessage<CreateShipmentCommand>(m => m.Id = id);
        }

 public class CommandHandler : IHandleMessages<CreateShipmentCommand>
    {
        public IBus Bus { get; set; }
        public void Handle(CreateShipmentCommand message)
        {
            Bus.Send(new CreatedShipmentEvent {ShipmentId = message.Id});
            Bus.Send(new CreateBookingCommand {ShipmentId = message.Id});
        }
    }

    public class CreateBookingCommand : IMessage
    {
        public Guid ShipmentId;
    }

    public class CreatedShipmentEvent : IMessage
    {
        public Guid ShipmentId;
    }

    public class CreateShipmentCommand : IMessage
    {
        public Guid Id { get; set; }
    }

bus is in the loop tho all msg it cast to type but can be diff type