pip install imqtt

python setup.py install

$ imqtt

In [1]: c = TCPClient(host = '127.0.0.1', port = 1883)
('connected to', '127.0.0.1', 1883)

In [2]: p = ConnectPacket()

In [3]: c.Send(p)
Out[3]: <__main__.TCPClient instance at 0x215c518>

In [4]: ack = c.Recv()

In [5]: ack
Out[5]: <ConnackPacket <FixedHeader ControlPacketType: 0x2, ControlPacketFlags: 0, RemainingLength: 2>, Flags: 0x1, ReturnCode: 0x0>

In [6]: pp = PublishPacket(Topic = '/imqtt/test', Payload = 'Hello world', QoS = 1, PacketID = 1)

In [7]: pp
Out[7]: <PublishPacket <FixedHeader ControlPacketType: 0x3, ControlPacketFlags: 0, RemainingLength: 0>, Dup: 0, QoS: 1, Retain: 0, PacketID: 1, Topic: /imqtt/test, Payload: Hello world>

In [8]: c.Send(pp).Recv()
Out[8]: <PubackPacket <FixedHeader ControlPacketType: 0x4, ControlPacketFlags: 0, RemainingLength: 2>, PacketID: 1>

Welcome to imqtt !
An iteractive MQTT packet manipulation shell based on IPython.
Github: https://github.com/shafreeck/imqtt

In [1]: s = TCPServer(host = '127.0.0.1', port = 1883)
listening on 127.0.0.1 1883

In [2]: s.Serve()

Packet received

This is an interactive environment, and being triggered when there was a packet received.
There are some varibles you can use:
 self: the tcp server object
 buf : current data received
 p   : the packet that unmarshaled from buf
Also, all python features are avaliable. Type 'exit()' or press 'Ctrl-D' to quit the shell.

In [1]: p
Out[1]: <ConnectPacket <FixedHeader ControlPacketType: 0x1, ControlPacketFlags: 0, RemainingLength: 17>,  Protocol: bytearray(b'MQTT'), Version: 4, <Flags UsernameFlag: 0, PasswordFlag: 0, WillRetain: 0, WillQoS: 0, WillFlag: 0, CleanSession: 1>, KeepAlive: 300, ClientID: bytearray(b'imqtt'), Username: , Password: >

In [2]: self.Send(ConnackPacket())
Out[2]: <imqtt.TCPServer at 0x10b890e10>

In [3]: exit()
Continue to serve...