Question

I am mocking in this sort of situation:

class A
{
    public IB B {get; set;}
}

interface IB
{
  //methods
}

class B : IB
{
  //IB methods
}

public SimpleMockTest()
{
   var mockIB = new Mock<IB>();
   var a = new A{B=mockIB.Object};
   //do stuff with A, then verify methods on IB were called       
}

public TheKindOfTestIWantToDo()
{
   var actualB = new B();
   var mockIB = new Mock<IB>();
   var splitter = new Splitter<IB>(actualB, mockIB.Object); //I need something like this
   var a = new A{B=splitter};
   //do stuff with A, methods invoked on splitter IB get passed to both supplied instances
   //of IB (actualB, and the mockIB). Allowing me to verify the calls as well as have the methods invoked on the actual B object.
   //OR:
   var mockIB2 = new Mock<IB>(actualB); //behaviour is dictated by the actual, but allows verification
   var a2 = new A{B=mockIB2.Object};
}

So I am after some sort of proxy factory that would genericly support an interface and call the same method on multiple interfaces. Of course where a method returns a value, each would need to return the same value, or maybe one takes precident.

I want to effectively snoop on interface calls during the test, but without the mock being the end of the line.

Am using Moq if it makes any difference.

Answer 1

As far as I know, there isn’t a way to do this for all methods on actualB.

I think you want something like:

public TheKindOfTestIWantToDo()
{
   var actualB = new B();
   var mockIB = new Mock<IB>();
   mockIB.Setup(b => b.Foo()).Returns(() => actualB.Foo())
   var a = new A { B = mockIB };
   //do stuff with A, methods invoked on splitter IB get passed to both supplied instances
   //of IB (actualB, and the mockIB). Allowing me to verify the calls as well as have the methods invoked on the actual B object.
}

You should probably rethink your unit testing strategy, though. The behavior of A should be testable without relying on the behavior of B. Try having mockIB return specific values, and then write a different set of tests for B.