Although correctly setting up your Unit Testing is pretty much a mess and a time sink on XCode (thanks to the very clear messages you get, as you found out), in your case I think the problem is your approach.
If you have several static libraries linked from multiple projects, the tests for the static libraries should not be run from the projects referencing them. Each library should be self-contained and pack it's own tests, and they should be run whenever you change something in that particular library.
The idea is that you should only be testing your own code. If you link an external static library, that library's author is responsible for correctly unit testing this portion. The fact that you're also the author of the external library should not have an impact on this.