Child class setUpTestData is not called when time_machine is used as a class decorator for Django tests

[vkhudiakova]

Python Version

3.11

pytest Version

No response

Package Version

2.13.0

Description

Here is a repository with example: https://github.com/vkhudiakova/time-machine-bug
If I use time_machine as a class decorator for the base class, that is inherited from Django TestCase, then the child setUpTestData method is not called.

from datetime import datetime

import time_machine
from django.test import TestCase


@time_machine.travel(datetime(2023, 1, 1))
class BaseTest(TestCase):
    @classmethod
    def setUpTestData(cls):
        super().setUpTestData()
        print('Base class method')


class ChildTest(BaseTest):
    @classmethod
    def setUpTestData(cls):
        super().setUpTestData()
        print('Child class method')

    def test_something(self):
        self.assertTrue(False)

Expected result:
Test outputs:

Base class method
Child class method

Running both base and child classes' setUpTestData methods.

Actual result

Test outputs only Base class method

If @time_machine decorator is removed from the class, the test works as expected.

[adamchainz]

Aww dammit. Class decorators are hard to get right.

Can you try recreating this in a test case in time-machine’s test suite? Rather than using setUpTestData, since there’s no Django in the project, you should be able to get the same effect with setUpClass. (Django’s setUpClass calls setUpTestData.) Run the tests with tox, such as tox -e py311 for Python 3.11.

[vkhudiakova]

@adamchainz Thank you for the quick response and for the library :)
I'll take a look at the test suite.

[bp72]

Hi! I added a small failing test, I hope it'll help!
#404

[adamchainz]

Fixed in #404 which has been released.

[vkhudiakova]

Thank you for the fix!