What is the right way to mock void functions in RhinoMocks?

Question

I have this interface that returns void in some functions that I would like to mock and wonder what is the correct way of doing so. As of now I have the following:

var mocks = new MockRepository();
var mockedInterface = mocks.CreateMock<IMyInterface>();
Expect.Call(mockedInterface.FunctionThatReturn(param1, param2)).Return(Something);
mockedInterface.FunctionReturningVoid(param3, param4);
mocks.ReplayAll();

// Some assert and other stuff
mocks.VerifyAll();

Is that the right way of doing it? I think it looks weird since you're not handling the two functions the same way. What I would like to write is:

var mocks = new MockRepository();
var mockedInterface = mocks.CreateMock<IMyInterface>();
Expect.Call(mockedInterface.FunctionThatReturn(param1, param2)).Return(Something);
Expect.Call(mockedInterface.FunctionReturningVoid(param3, param4)); // This doesn't work.
mocks.ReplayAll();

// Some assert and other stuff
mocks.VerifyAll();

But that doesn't work on row 4. I found some blog that says you can use lambdas (or delegate) like

Expect.Call(() => mockedInterface.FunctionReturningVoid(param3, param4)); // This doesn't work.

But that doesn't seem to work either for me. Having the Expect.Call makes it easy to identify mocked functions and that is why I want it. The compile error I get is: "Cannot convert lambda expression to type 'object' because it is not a delegate type".

So how should it be done?

UPDATE: Added compile error information.

Answer 1

I prefer the AAA (arrange/act/assert) syntax instead of record/replay. It's more straightforward and makes the tests easier to read. What you'll want to do is:

// arrange
var mock = MockRepository.GenerateMock<IMyInterface>
mock.Expect(i => i.FunctionThatReturnSomething(param1, param2)).Return("hello");
mock.Expect(i => i.FunctionThatReturnVoid(param3, param4));
// set up other stuff for your code (like whatever code depends on IMyInterface)
var foo = new Foo(mock);

// act
foo.DoSomething();

// assert
mock.VerifyAll();