Tell unittest.main not to exit, fixes #850.

setuptools/command/test.py

@@ -225,10 +225,12 @@ class test(Command):
                         del_modules.append(name)
                 list(map(sys.modules.__delitem__, del_modules))
 
+        exit_kwarg = {} if sys.version_info < (2, 7) else {"exit": False}
         unittest_main(
             None, None, self._argv,
             testLoader=self._resolve_as_ep(self.test_loader),
             testRunner=self._resolve_as_ep(self.test_runner),
+            **exit_kwarg
         )
 
     @property