CODEWITHSUNDEEP
pythonunit-testingtestingpytesttestunit
user428745
user428745

Reputation: 853

How can I mock a abastract class or interface in Python using - testing with pytest

I create an interface to provide email validation for my controller

class EmailValidatorInterface(ABC):
    """ Interface to EmailValidator use case """

    @abstractmethod
    def is_valid(self, email: str) -> bool:
        """ Specific case """

        raise Exception("Should implement method: is_valid")

That is my controller implementation

class SignUpController(RouteInterface):
    def __init__(self, emailValidator: EmailValidatorInterface):
        self.emailValidator = emailValidator

    def route(self, http_request: Type[HttpRequest]) -> HttpResponse:

How can I create a mock for my EmailValidator? I'm trying to use mock.patch but I don't how to initialize the mock

Look at my test

def test_should_return_400_if_invalid_param_is_provided():

    with mock.patch('EmailValidatorStub') as MockEmailValidator:
        MockEmailValidator.return_value.is_valid.return_value = False

    sut = SignUpController(EmailValidatorStub())
    attributes = {
        "name": faker.word(),
        "login": faker.word(),
        "email": "any_email",
        "email_confirmation": "[email protected]",
        "password": "any_password",
        "password_confirmation": "any_password"
    }

    request = HttpRequest(body=attributes)
    httpResponse = sut.route(request)
    assert httpResponse.status_code == 500

Upvotes: 2

Views: 2203

Answers (1)

Code-Apprentice
Code-Apprentice

Reputation: 83557

I don't think you need mock.patch here since you can just use dependency injection. In other words, just create a subclass like you normally would, but add implementation that is specific to the test:

class MockValidator(EmailValidatorInterface):
   pass

Then instantiate it in your test:

sut = MockValidator()

You can either create a separate mock class for each scenario you are testing or add a __init__() method that takes parameters that can vary between each scenario. Or some combination of the two. Mocks shouldn't contain any logic but instead just satisfy a specific scenario that is tested.

Upvotes: 4

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