Mocking class attributes and methods with Python and Pytest

Question

I'm trying to Mock a class using pytest-mock but I don't quite understand how to do it, even after reading articles everywhere.

The thing is I have a class called Model which one of the attributes returns a list of other elements of different objects inside the model Line, Square, Circle, etc. The Model is generated by reading a huge file and it will be used in many places throughout the application, so I turned into mocking it, because in this phase I just want to check if it works as expected.

I'm using pytest-mock, but it's not very clear for me. I've tried:

def test_parse_find_elements_by_name(parser, mocker):
    
    def mock_objects(self):
        return ["a","b","c"]

    model = Model()
    mocker.patch(
        "orcaflow.Model.objects",
        mock_objects
    )
    
    assert model.objects == ["a", "b", "c"]

But it returns a method, not an attribute (with the @property decorator). A work around was to use the mock package by itself:

@pytest.fixture
def mocked_model(mocker):
    objects = []
    for i in range(10):
        obj = MagicMock()
        obj.name = "Line %d" % i
        objects.append(obj)
    
    model = Mock(objects = objects )
    return model

Is there a way to do it directly with pytest-mock or some way smarter to do it?

Are you trying to mock a property? In this case you should use a [PropertyMock](https://docs.python.org/3/library/unittest.mock.html#unittest.mock.PropertyMock). — MrBean Bremen, Dec 30 '20 at 09:34
I'm trying to use the pytest-mock plugin in this case. For now i'm using the workaround that I wrote. I see how he's doing in the link you send, and if I can't find how to do it, i'll adopt it. — Eug_Zazou, Dec 30 '20 at 09:47
There is a [specific answer](https://stackoverflow.com/a/59615277/12480730) for pytest-mock to the question. — MrBean Bremen, Dec 30 '20 at 09:48

Mocking class attributes and methods with Python and Pytest

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