CODEWITHSUNDEEP
mockingpytestfixtures
Milan
Milan

Reputation: 1750

Pytest: Use a mock in a fixture?

This question is a follow up on my previous question, here

I would like to define a fixture that will run a function for each of it's parameters, before returning it to me.

However, the function cannot run without another validation function being mocked, because the validation cannot be performed without a file system.

Here is what it looks like currently:

mocked_validation = mock.Mock() mocked_validation.return_value = True

@pytest.fixture(params = GAMELIST_ROOT_VALUES) def basic_parser(request):
    return GameListParser(request.param)

@pytest.fixture @mock.patch('organizer.parser.game_list_parser.GameListParser.validate', mocked_validation) def ready_parser(basic_parser):
    basic_parser.parse()
    return basic_parser

However the fixture will fail at the basic_parser.parser() call, during the validation.

I use this mock for tests, it works well, so it must have to do with the fact that it's in a fixture.

Is there anyway to do that ? I do not wish to repeat this line of code for every test

This can be tested with the following class:

class GameListParser(object):

    def __init__(self, value):
        self.value = value

    def parse(self):
        if not self.validate():
            raise Exception("Parsing fail")

    def validate(self):
        return False

Edit: Adding another try, but still failing:

@pytest.fixture
def ready_parser(basic_parser):
    with mock.patch('organizer.parser.game_list_parser.GameListParser.validate') as validation:
        validation.return_value = True
        basic_parser.parse()
        return basic_parser

Upvotes: 1

Views: 4445

Answers (1)

Milan
Milan

Reputation: 1750

Found solution with yield:

@pytest.fixture()
def ready_parser(basic_parser):
    with mock.patch('organizer.parser.game_list_parser.GameListParser.validate') as validation:
            validation.return_value = True
            basic_parser.parse()
            yield basic_parser

But I feel sad I cannot reuse the definition I already have for mocked_validation, I tried again as a decorator and it's not working

Upvotes: 2

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