Raise event of mocking object and passing there as argument object used for calling method

Question

I have an interface IPeakCommunication, and derived class PeakCommunication. Inside derived class I have an implementation of method Send(RequestData request) which do something, and as I expect invokes event RequestReceived and passing there argument request.

I would to create unit tests for some classes which interact with IPeakCommunication, and call Send(RequestData request) method. But I have no idea how to create a Mock which takes an object from arguments and use it for invoking RequestReceived event.

public interface IPeakCommunication : IDisposable
{
#region Delegates
delegate void PeakRequestReceivedHandler(RequestData data);
#endregion

#region Events
event PeakRequestReceivedHandler? RequestReceived;
#endregion

#region Methods
void Send(RequestData data);
#endregion
}

The code which I tried to make:

var mockCommunication = new Mock<IPeakCommunication>();
mockCommunication.Setup(x => x.Send(It.IsAny<RequestData>()))
    .Raises(x => x.RequestReceived += null, new object[] { /*argument from Send()?*/ } );

Answer 1

You can use Callback:

var mockCommunication = new Mock<IPeakCommunication>();

// Setup with callback which uses Raise
mockCommunication.Setup(x => x.Send(It.IsAny<RequestData>()))
    .Callback((RequestData rd) => 
        mockCommunication.Raise(c => c.RequestReceived += null, rd));

// Act
var obj = mockCommunication.Object;
// sample subscriber:
obj.RequestReceived += rd => Console.WriteLine(rd.Data);
obj.Send(new RequestData { Data = 42 }); // Prints 42

// sample data object
public class RequestData
{
    public int Data { get; set; }
}

Demo @dotnetfiddle.net