dj-pytest

Pytest for op-django

Testing in this project is layered the same way the code is. Each layer has its own rules, its own fixtures, and its own performance characteristics. The goal is to keep the fast tests fast — service tests should never touch a database — and to isolate the slow tests at the edges.

The Three Layers

File	What it covers	DB?	Speed
test_repo.py	ORM ↔ DTO conversion, prefetches, transactions, ID prefixes	✅ real	slow
test_service.py	Business logic, validation, orchestration	❌ mocked	fast
test_api.py	HTTP integration — request → view → service → repo	✅ real	slow

Service tests are the most valuable layer and should outnumber the others. If a service test needs @pytest.mark.django_db, something has leaked — find the ORM call and push it into a repository.

Dependencies

uv add --dev pytest pytest-django pytest-xdist freezegun pytest-mock

• pytest-django — the django_db marker, client fixture, settings integration, django_capture_on_commit_callbacks.
• pytest-xdist — -n auto parallel runs. Keep it out of addopts so debugger runs stay serial.
• pytest-celery is deliberately absent — tasks are never executed through Celery machinery in tests (see Celery in Tests).
• freezegun — freezes datetime.now(), time.time(), and friends. Required for any logic that touches timestamps, TTLs, scheduled work, or ULIDs whose sort order matters to the test.
• pytest-mock — the mocker fixture (a thin wrapper around unittest.mock with autouse cleanup).

Configuration

Add to pyproject.toml:

[tool.pytest.ini_options]
DJANGO_SETTINGS_MODULE = "project.settings"
python_files = ["test_*.py"]
pythonpath = ["src"]
addopts = [
    "-ra",
    "--strict-markers",
    "--strict-config",
]
markers = [
    "slow: deselect with '-m \"not slow\"'",
]

Notes:

• pythonpath = ["src"] is what lets from project.services import get resolve without an editable install.
• --strict-markers catches typos in @pytest.mark.xxx. --strict-config does the same for the config file.
• Keep the markers list small and meaningful — one or two genuine custom markers maximum.