environment/lib/python2.7/site-packages/nose/selector.py
def wantClass(self, cls):
        """Is the class a wanted test class?

        A class must be a unittest.TestCase subclass, or match test name
        requirements. Classes that start with _ are always excluded.
        """
        declared = getattr(cls, '__test__', None)
        if declared is not None:
            wanted = declared
        else:
            wanted = (not cls.__name__.startswith('_')
                      and (issubclass(cls, unittest.TestCase)
                           or self.matches(cls.__name__)))
        
        plug_wants = self.plugins.wantClass(cls)        
        if plug_wants is not None:
            log.debug("Plugin setting selection of %s to %s", cls, plug_wants)
            wanted = plug_wants
        log.debug("wantClass %s? %s", cls, wanted)
        return wanted
def wantClass(self, cls):
        """Is the class a wanted test class?

        A class must be a unittest.TestCase subclass, or match test name
        requirements. Classes that start with _ are always excluded.
        """
        declared = getattr(cls, '__test__', None)
        if declared is not None:
            wanted = declared
        else:
            wanted = (not cls.__name__.startswith('_')
                      and (issubclass(cls, unittest.TestCase)
                           or self.matches(cls.__name__)))
        
        plug_wants = self.plugins.wantClass(cls)        
        if plug_wants is not None:
            log.debug("Plugin setting selection of %s to %s", cls, plug_wants)
            wanted = plug_wants
        log.debug("wantClass %s? %s", cls, wanted)
        return wanted
Is the class a wanted test class?

        A class must be a unittest.TestCase subclass, or match test name
        requirements. Classes that start with _ are always excluded.