How to mock instance attribute of django form

Question

I'm doing a unit test where I'm mocking a Django form, but I'm having some trouble because I need to mock two things from the form:

An instance attribute (token)
A method (is_valid)

I'm using the form in a view, importing it like this:

from profiles.forms import PaymentForm

And I have tried the following to mock it:

    @patch('profiles.forms.PaymentForm')
    def test_when_processing_a_payment_then_the_event_is_tracked(self, payment_form_class):
        payment_form_class.is_valid.return_value = True
        payment_form_class.cleaned_data = {'token': 1}

This approach does not work, is_valid returns false.

    @patch('profiles.forms.PaymentForm')
    def test_when_processing_a_payment_then_the_event_is_tracked(self, payment_form_class):
        payment_form_class.return_value.is_valid = True
        payment_form_class.return_value.cleaned_data = {'token': 1}

This neither.

I'm using Django and unittest. I have successfully mocked the is_valid with a helper function of our code base, but it does not seem to work with instance attributes. Any idea how to solve this?

You might need to mock the form on where it is used in your view since it's already imported there before your mock runs. So something like: `my_app.my_views.PaymentForm` — Brian Destura, Feb 21 '22 at 07:04
Lol it was that, I always forgot the correct path in the patch, Thanks! Pls post it as an answer :) — Antonio Gamiz Delgado, Feb 21 '22 at 07:07

score 1 · Accepted Answer · answered Feb 21 '22 at 21:40

1

You might need to mock the form on where it is used in your view since it's already imported there before your mock runs.

So something like:

@patch('my_app.my_views.PaymentForm')

answered Feb 21 '22 at 21:40

Brian Destura

11,487
3
18
34

How to mock instance attribute of django form

1 Answers1