'Socket reads with an unknown socket error are raised.'

def test_readUnknownError(self):

    protocol = KeepReads()
    port = udp.Port(None, protocol)
    port.socket = StringUDPSocket(['good', socket.error((-1337))])
    self.assertRaises(socket.error, port.doRead)
    self.assertEqual(protocol.reads, ['good'])
