Our "main" solution is the development code: shared libraries, services, UI projects, etc. The other solution is an integration and automated tests solution. It references several of the development projects. The reason it is separate is to avoid interference with the development solution's unit test VSMDI file. And to allow us to play with different execution methods (other test runners, like Gallio or StoryTeller) without interfering with the development solution.

Recently, an interface changed in the development solution, one of our test mocks implemented that interface. But, it was not updated because there was no warning at compile time because it was in another solution. This broke our CI build.

Does anyone have a similar setup? How do you handle these issues, do you follow a strict procedure or is there some kind of technical answer?