pytest-django not picking up pytest sys.path auto-config for DJANGO_SETTINGS_MODULE

pytest automatically adds the first directory without a __init__.py to the sys.path when discovering tests.

Eg with the following structure:

.
├── AUTHORS
├── CHANGELOG.rst
├── COPYING
├── some_django_app
│   ├── __init__.py
│   ├── management
│   │   ├── commands
│   │   │   └── __init__.py
│   │   └── __init__.py
│   ├── middleware.py
│   └── templatetags
│       └── __init__.py
├── README.rst
├── setup.cfg
├── setup.py
├── tests
│   ├── conftest.py
│   ├── testproject
│   │   ├── __init__.py
│   │   ├── settings.py
│   │   └── urls.py
│   └── test_xyz.py
└── tox.ini

When running tests, "tests/" is added to the sys.path, and in places like conftest.py you can add:

from django.conf import settings

from testproject import settings as testproject_settings


def pytest_configure():
    settings.configure(**vars(testproject_settings))

However it appears as though simply adding DJANGO_SETTINGS_MODULE="testproject.settings" does not work.

Inspect tests/conftest.py and tests/testproject/settings.py, then run tests/test_xyz.py while comparing the working settings.configure path with DJANGO_SETTINGS_MODULE during test discovery. Done means DJANGO_SETTINGS_MODULE loads testproject.settings with the shown layout and the behavior is covered by the relevant test.