Mock attributes in Python mock? Mock attributes in Python mock? python python

Mock attributes in Python mock?


You need to use return_value and PropertyMock:

with patch('requests.post') as patched_post:    type(patched_post.return_value).ok = PropertyMock(return_value=True)

This means: when calling requests.post, on the return value of that call, set a PropertyMock for the property ok to return the value True.


A compact and simple way to do it is to use new_callable patch's attribute to force patch to use PropertyMock instead of MagicMock to create the mock object. The other arguments passed to patch will be used to create PropertyMock object.

with patch('requests.post.ok', new_callable=PropertyMock, return_value=True) as mock_post:    """Your test"""


With mock version '1.0.1' the simpler syntax mentioned in the question is supported and works as is!

Example code updated (py.test is used instead of unittest):

import mockimport requestsdef method_under_test():    r = requests.post("http://localhost/post")    print r.ok    if r.ok:        return r.ok    else:        raise Exception()def test_method_under_test():    with mock.patch('requests.post') as patched_post:        patched_post.return_value.ok = True        result = method_under_test()        assert result is True, "mock ok failed"

Run this code with: (make sure you install pytest)

$ py.test -s -v mock_attributes.py ======= test session starts =======================platform linux2 -- Python 2.7.10 -- py-1.4.30 -- pytest-2.7.2 -- /home/developer/miniconda/bin/pythonrootdir: /home/developer/projects/learn/scripts/misc, inifile: plugins: httpbin, covcollected 1 items mock_attributes.py::test_method_under_test TruePASSED======= 1 passed in 0.03 seconds =================