Mocking a class within a mock interface

You are basicly wanting chained calls.
Using Natural Mocks this is easy. Just call it.

ITrackingView tracker = 
 RecorderManager.CreateMockedObject(typeof(ITrackingView));

using (RecordExpectations recorder = RecorderManager.StartRecording())
{
    tracker.SessionTracking.UserAgent;
    recorder.Return(fakeAgent);
}

If you don't have a license, you can create all the objects manually.

// create Session type and make sure that the fake agent is returned
MockObject mockSession = MockManager.MockObject(typeof(SessionTracking)); 
mockSession.ExpectGet("UserAgent",fakeAgent);

// make sure that our mocked session will be returned when SessionTracking is called
MockObject mockInterface = MockManager.MockObject(typeof(ITrackingView)); 
mockInterface.ExpectGet("SessionTracking",mockSession.Object);

Thanks for you help. Chaining was what I was looking at, but I only have the Professional version. This has solved my problem up to the next point.

Unit Test

...
MockObject mockSessionTracking = MockManager.MockObject(typeof(SessionTracking));
mockSessionTracking.ExpectGet("UserAgent", session.Agent);

MockObject mockInterface = MockManager.MockObject(typeof(ITrackingView));
mockInterface.ExpectGetAlways("SessionTracking", mockSessionTracking.Object);
...

At this point the mockSessionTrack object has a value for the UserAgent property.

Code
void AddTracking(object sender, EventArgs e)
{
TrackingServiceClient client = new TrackingServiceClient("...");
Session session = new Session();

session.Agent = _tracking.SessionTracking.UserAgent; // FAILS
...
}

But on the _tracking.SessionTracking.UserAgent property it is throws a System.NullReferenceException. For some reason the value is not being translated from the mockSessionTracking UserAgent property to the _tracking.SessionTracking.UserAgent property.

Thanks,
Eric

This really depends on other parts of the code.
Perhaps _tracking is not set to your mock object, check how to pass the mock object into the code.
Perhaps the session.Agent you are returning is null.

:arrow: Take a look at the tracer to see which instance and method is not being called.

I figured out what the problem was.

Unit Test
...
MockObject mockSessionTracking = MockManager.MockObject(typeof(SessionTracking));
mockSessionTracking.ExpectGet("UserAgent", session.Agent);

MockObject mockInterface = MockManager.MockObject(typeof(ITrackingView));
mockInterface.ExpectGetAlways("SessionTracking", mockSessionTracking.Object);
...

The UserAgent property in the mockSessionTracking object would return the value correctly the first time, because it was an ExpectedGet call. For some reason I believe that the ExpectGet fired when I created the mockInterface and set the mockSessionTracking.Object to the SessionTracking Get property. At this point the UserAgent property would throw a System.NullReferenceException.

To fix this I did the following. Set the UserAgent property to ExpectGetAlways. Then it works all the way through the unit test where the the actual call is made to the UserAgent property.

Unit Test
...
MockObject mockSessionTracking = MockManager.MockObject(typeof(SessionTracking));
mockSessionTracking.ExpectGetAlways("UserAgent", session.Agent);

MockObject mockInterface = MockManager.MockObject(typeof(ITrackingView));
mockInterface.ExpectGetAlways("SessionTracking", mockSessionTracking.Object);
...

Thanks for you help,
Eric