'subclasses can assign attributes'

def test_subclass(self):

    class S(zmq.Socket, ):
        a = None
        def __init__(self, *a, **kw):
            self.a = (-1)
            super(S, self).__init__(*a, **kw)
    s = S(self.context, zmq.REP)
    self.sockets.append(s)
    self.assertEqual(s.a, (-1))
    s.a = 1
    self.assertEqual(s.a, 1)
    a = s.a
    self.assertEqual(a, 1)
