def METHOD_NAME(self):
    self.game['a1'] = 'x'
    self.game['b2'] = 'o'
    self.game['b1'] = 'x'
    self.game['a2'] = 'o'
    self.game['c2'] = 'x'
    self.assertEqual(None, self.game.winner())
    self.game['c3'] = 'o'
    self.game['c1'] = 'x'
    self.assertEqual('X', self.game.winner())