Rhino Mocks Stub different instances on return

Question

I'm looking for a way to make my tests more clear, this is the problem:

public interface A
{

}

public interface B
{
    A GetA();
}

Now, if I want a stub on B, and a new instance everytime I call GetA, i do this:

[Test]
public void TestName()
{
     MockRepository mockery = new MockRepository();

     B b = mockery.Stub<B>();
     b.Stub(x => x.GetA()).Return(mockery.Stub<A>()).Repeat.Once();
     b.Stub(x => x.GetA()).Return(mockery.Stub<A>()).Repeat.Once();

     mockery.ReplayAll();

     Assert.IsFalse(ReferenceEquals(b.GetA(), b.GetA()));
}

Note that in assert I call GetA twice, and I have setup the results as a Repeat.Once() instead of Repeat.Twice();

If you run this test, it will pass, because the instances are different. Howerver, I don't find this code very clear this way. How do you make Rhino Mocks generate new instance on every call?

Note: In the past I've used many tricks like on every return using Do() to execute some code that changes the instance and such, but is there something like .GenerateNewInstance() or similar?

Answer 1

[Test]
public void TestName()
{
      var b = MockRepository.GenerateStub<B>();
      b.Stub(x => x.GetA())
          .WhenCalled(x => x.ReturnValue = MockRepository.GenerateStub<A>());

      Assert.IsFalse(ReferenceEquals(b.GetA(), b.GetA()));
}

In some instances you must explicitly add the .Return() call, but the value will be overridden if you set ReturnValue in the WhenCalled delegate argument.