While I think I get where the OP is going, this seems just too easy to claim without any real-life code. So let's try this then. The last time I used mocks: we'

While I think I get where the OP is going, this seems just too easy to claim without any real-life code. So let's try this then. The last time I used mocks: we're interfacing with motor control hardware. In code we have interfaces for axis configuration, axis movement and so on. All implemented for different controllers. On top of that there's a layer defining specific movements. Say you want to go from point a to b while avoiding c, there's a piece of code that calculates a route (so it needs axes configurations for max velocity/range/...) and another piece that applies this route to a set of axes (so it needs axes to drive). Apart from dragging around a bunch of motors everywhere I code, how am I supposed to properly test those two pieces without any mocks? Telling me the design is all wrong to start with is fine, but then you also have to come up with a better one of course :). Telling me that route calculation shouldn't depend directly on axis configuration but should use it's own configuration type and I should then add a conversion between the two is also no solution as it a) introduces an extra layer and b) still requires a mock to test the conversion, d'uh :)