@Patch decorator is not compatible with pytest fixture

Question

I have encountered something mysterious, when using patch decorator from mock package integrated with pytest fixture.

I have two modules:

    -----test folder           -------func.py           -------test_test.py 

in func.py:

    def a():         return 1      def b():         return a()      

in test_test.py:

    import pytest     from func import a,b     from mock import patch,Mock      @pytest.fixture(scope="module")     def brands():         return 1       mock_b=Mock()      @patch('test_test.b',mock_b)     def test_compute_scores(brands):                           a() 

It seems that patch decorate is not compatible with pytest fixture. Does anyone have a insight on that? Thanks

Answer 1

When using pytest fixture with mock.patch, test parameter order is crucial.

If you place a fixture parameter before a mocked one:

from unittest import mock  @mock.patch('my.module.my.class') def test_my_code(my_fixture, mocked_class): 

then the mock object will be in my_fixture and mocked_class will be search as a fixture:

fixture 'mocked_class' not found 

But, if you reverse the order, placing the fixture parameter at the end:

from unittest import mock  @mock.patch('my.module.my.class') def test_my_code(mocked_class, my_fixture): 

then all will be fine.