title: Does Python Tools for Visual Studio support discovering unit tests when using any python interpreter other than IronPython?
body: <p>I have a couple of ActiveState python 2.7 interpreters, and one IronPython interpreter in my Python environments setup and in the same project. Whenever I switch to make IronPython interpreter the active one, Visual Studio Test Explorer is able to discover and run the tests. Switching to any other interpreter fails to discover any tests (so 0 tests are run if I do "run all"). Interestingly running 'python.exe -m unittest discover' works for any of those interpreters. 
  Is this a known issue, or is anyone able to use non-IronPython interpreter and still discover unit tests in Visual Studio Test Explorer?</p>