If next statements are true for this project:
1. No need in special possibilities of specific test framework (will never contain complex tests).
2. Should be run by most devs without modification of their environments.
3. All tests are simple(short) and just say that nothing was forgotten, writing tests(putting attributes) should be automated or fast(like short attributes names).
4. Wrappers are generic (can be split for and used on different CLR implementations)
In this case it is the best to choose NUnit as integrated into SharpDevelop, MonoDevelop, VS2010+ReSharper, Gallio, VS2012.