Django: All subsequent tests fail after one test fails

Question

I've moved recently from Python 2.7 to Python 3.8. There's a strange new phenomenon when running the tests, that can be reproduced with this simple example:

from django.test import TestCase
from users.models import User


class TestWTF(TestCase):
    def setUp(self):
        self.user = User.objects.create(email='admin@project.com')

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

    def test_success(self):
        pass

When test_failure() fails the self.user object doesn't get removed from the DB. It seems like the promised rollback feature just doesn't happen. test_success() and all subsequent tests in the same class will fail with UNIQUE constraint being violated when setUp() tries to create the object again.

It doesn't happen in Python 2.

A partial output from pytest I'm using:

$ pytest -W ignore -s
================================================= test session starts ==================================================
platform linux -- Python 3.8.2, pytest-5.4.1, py-1.8.1, pluggy-0.13.1
django: settings: project_sites.settings.tests (from ini)
rootdir: /home/emes/devel/project/project, inifile: pytest.ini
plugins: django-3.8.0, env-0.6.2, case-1.5.3, cov-2.8.1
collected 2 items
[...]
=============================================== short test summary info ================================================
FAILED deals/tests/test_wtf.py::TestWTF::test_failure - AssertionError: False is not true
FAILED deals/tests/test_wtf.py::TestWTF::test_success - django.db.utils.IntegrityError: UNIQUE constraint failed: use...
================================================== 2 failed in 22.76s ==================================================

edit: I'm using Django-1.11.26

You should remove the user in the `tearDown`: https://docs.python.org/3/library/unittest.html#unittest.TestCase.tearDown. — Willem Van Onsem, May 26 '20 at 15:30
My hunch is something in your project is interfering with Django's test isolation. — Ken Kinder, May 26 '20 at 15:33
I can't reproduce your error with Python 3.8 and Django 3.0.6. — Alasdair, May 26 '20 at 16:47
I don't get the error with Python 3.8/Django 1.11.29 either. Note that Django 1.11 doesn't officially support Python 3.8. — Alasdair, May 27 '20 at 08:37
If you use `pytest` instead of `django.test.TestCase` your tests will automatically do their own tear down each and every time... whether they pass or fail, just saying! — Farhan Kathawala, May 28 '20 at 06:10

score 0 · Answer 1 · answered Jul 02 '20 at 15:07

0

I had the same issue with Django 2.2 on Python 3.6.

I was using pytest 5.4.1 and pytest-django 3.8.0.

Updating pytest-django to version 3.9.0 resolved the issue, so I believe it was an issue in 3.8.0.

answered Jul 02 '20 at 15:07

Sam Hartsfield

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Django: All subsequent tests fail after one test fails

1 Answers1