'L{telnet.Telnet.requestNegotiation} formats the feature byte and the
payload bytes into the subnegotiation format and sends them.
See RFC 855.'

def test_requestNegotiation(self):

    transport = proto_helpers.StringTransport()
    self.protocol.makeConnection(transport)
    self.protocol.requestNegotiation('\x01', '\x02\x03')
    self.assertEqual(transport.value(), '\xff\xfa\x01\x02\x03\xff\xf0')
