Test can not be run individually for apps that have tests.suite() defined
|Patch needs improvement:
This issue shows up if the tests are defined in the application using the suite(). The django.test.simple.build_suite() function has support for such arrangement (which is why testing the whole app works), but django.test.simple.build_test() does not which is why running a single test class or test case fails. The fix would be to call build_suite in build_test and then iterate over the TestSuite, just like it is done in the Doctest code in the same function.