testing

name	testing
description	Testing guidance for diplicity-react — frontend Vitest and backend pytest patterns, fixtures, conftest organisation, MSW mocks, and performance tips. Use when writing or running tests, setting up fixtures, or reviewing test code.
allowed-tools	Bash, Read, Glob, Grep, Write, Edit

Testing

Frontend

cd packages/web
npm run test                # all tests
npm run test <filename>     # single file (preferred — faster feedback)

Backend

# Single file (preferred)
docker compose run --rm service python3 -m pytest service/game/tests/test_game_create.py -v

# Single function
docker compose run --rm service python3 -m pytest service/game/tests/test_game_create.py::test_create_game_success -v

# Single method of a class
docker compose run --rm service python3 -m pytest service/game/tests/test_game_create.py::TestClass::test_method -v

# Full suite (use -n auto for parallel)
docker compose run --rm service python3 -m pytest -n auto -v

In native (non-Docker) cloud sessions:

cd service
python -m pytest game/tests/test_game_create.py -v    # single file
python -m pytest -n auto --reuse-db                   # full suite, reuse DB
python -m pytest -q --create-db                       # rebuild test DB (after new migrations)

SQLite is not viable. Some migrations use Postgres-only SQL. Always use the native PostgreSQL cluster.

Backend Testing Patterns

Where fixtures live

Shared fixtures → root service/conftest.py — check here before adding anywhere else.

Per-app conftest.py files exist only for genuinely app-local fixtures:

• login/conftest.py — Google/Apple auth and token mocks
• integration/conftest.py — autouse procrastinate mock + extra users/clients for 7-player games
• nation/conftest.py — draft variants and flag SVG data
• variant/conftest.py — SVG map builders (make_dsvg, make_godip_svg, etc.)

Fixture naming conventions

• *_factory — returns a callable that creates objects on demand. Always use this suffix for callable-returning fixtures; never make_* or bare names.
• Session-scoped reference data — read-only lookups: <variant_id>_variant, <variant_id>_<name>_nation, <variant_id>_<name>_province (e.g. classical_england_nation). Created once per session — never mutate in tests.
• Session-scoped users/clients — primary_user, secondary_user, tertiary_user and matching authenticated clients. Never mutate or delete; use user_factory for disposable users.
• Scenario fixtures — descriptive nouns returning ready-made objects (active_game_with_phase_state, game_with_two_members).
• mock_* — patch fixtures (mock_send_notification_to_users, mock_immediate_on_commit).

Performance

• Root conftest forces MD5PasswordHasher — create_user is cheap; do not use the production hasher in tests.
• Use pytest --reuse-db locally to skip recreating the database (~6s) between runs. Pass --create-db after pulling new migrations.
• Full suite is parallel-safe: pytest -n auto. Each worker gets its own database (test_diplicity_gwN). CI runs with -n auto. Not in addopts so single-file runs skip worker startup cost.
• No test uses django_db(transaction=True) — use mock_immediate_on_commit instead.

What good tests look like

• Test API endpoints, not model methods directly
• Assert on response status codes AND response body
• Include permission tests for endpoints with access control
• Assert on observable outcomes (HTTP responses, rendered text), not internal state
• Factory fixtures in conftest.py, not in the test file

Review check: tests hit API endpoints (not internal methods)? status code AND body asserted? permissions covered? fixtures follow naming conventions and live in conftest.py?