def test_failure_demo_fails_properly(): 

       config = py.test.config._reparse([failure_demo]) 

       session = config.initsession()

->     session.main()

       l = session.getitemoutcomepairs(Failed)

       assert len(l) == 21 

       l = session.getitemoutcomepairs(Passed)

       assert not l 

   def main(self): 

       """ main loop for running tests. """

->     colitems = self.config.getcolitems()

       try:

           self.header(colitems) 

           try:

               try:

                   for colitem in colitems: 

                       self.runtraced(colitem)

               except KeyboardInterrupt: 

                   raise 

           finally: 

               self.footer(colitems) 

       except Exit, ex:

           pass

       return self.getitemoutcomepairs(Failed)