So, despite my February posts to the contrary, last week I finally understood what Mock Objects are. Or more directly, I finally understood what they aren't. Martin Fowler's article entitled Mocks Aren't Stubs really laid it out well. Stubs are used for state-based testing. Mocks are used for interaction-based testing. Using a Mock when what you want is a Stub generally results in the interaction-testing features getting "in your way". This is the case for the www.mockobjects.com mock implementation of the various HTTPxxx interfaces. They add a lot of useful methods for testing interaction, but when all I want is to set attributes, they're "in the way".
Martin Fowler's Article: