'Instances of a class which mixes in L{FancyEqMixin} but which
defines no comparison attributes compare by identity.'

def test_identity(self):

    class Empty(util.FancyEqMixin, ):
        pass
    self.assertFalse((Empty() == Empty()))
    self.assertTrue((Empty() != Empty()))
    empty = Empty()
    self.assertTrue((empty == empty))
    self.assertFalse((empty != empty))
