It is possible to write integrating tests for AutoCAD .NET extensions through the Gallio and NUnit frameworks. But they can't be used for the unit tests writing (for AutoCAD). Have anybody experience of unit tests writing for AutoCAD through using other framework platforms (JustMock, TypeMock, etc)? If such developer is exists, then his impression about this experience would be interesting to me.
For me it seems very difficult to write such tests because it is necessary to write a lot of the mocks and stubs. Thus creation of the unit test requires necessary knowledge of the internal content of the tested code. It breaks encapsulation and can promote a brittleness of the test (in my opinion).
It is interesting to me whether costs of creation of the unit tests for AutoCAD, in addition to integration tests pay off.