How To Mock A Socket Object Via The Mock Library

How to mock a TCPSocket wrapper for the socket from the Python's standard libary via the mock library (unittest.mock in case of Python 3)? This is my wrapper: import socket import

Solution 1:

It can be as simple as

import mock   # or from unittest import mock


mock_socket = mock.Mock()
mock_socket.recv.return_value = data

then use mock_socket where you would use the real socket. You can also mock whatever creates the socket to return a mock value like the one configured here, depending on your needs.

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For your case, you can mock socket.socket so that it returns something whose method you can configure. Note that mock_socket in this example is a function that returns a Socket object, not a Socket object itself.

with mock.patch('socket.socket') as mock_socket:
    mock_socket.return_value.recv.return_value = some_data
    t = TCPSocket()
    t.connect('example.com', 12345)  # t.sock is a mock object, not a Socket
self.assertEqual(t.recv_bytes(), whatever_you_expect)
t.sock.connect.assert_called_with(('example.com', 12345))