Instruction file imported from azusa152/Folio (.cursor/rules/testing.mdc). Copyright stays with the author.

Backend Testing Standards (pytest)

Every feature MUST ship with tests. Bug fixes MUST include regression tests. No untested code in production.

Test File Structure

Tests live in backend/tests/ mirroring the source layout. Sub-packages mirror their source counterparts — e.g., tests/domain/analysis/ for domain/analysis/, tests/application/stock/ for application/stock/, tests/api/routes/ for api/routes/, tests/infrastructure/market_data/ for infrastructure/market_data/.

Test Naming

Use descriptive names: test_<function>_should_<expected_behavior>

AAA Pattern

Every test follows Arrange / Act / Assert. See backend/tests/ for canonical examples.

Fixtures & conftest.py

• conftest.py provides: TestClient, in-memory SQLite DB, mock yfinance data, mock Telegram sender.
• Use @pytest.fixture with appropriate scope (session for DB, function for per-test isolation).

Mock External Services

• yfinance, Telegram Bot API, and any network I/O MUST be mocked. Never hit real APIs in tests.
• Use unittest.mock.patch or pytest-mock to replace infrastructure adapters.
• Patch at the actual module, not a re-export shim. Private symbols (e.g., _fetch_signals_from_yf) must be patched at their definition site: infrastructure.market_data.market_data._fetch_signals_from_yf, not infrastructure.market_data._fetch_signals_from_yf.

Minimum Test Coverage Per Endpoint

Webhook Action Coverage

• Every webhook action MUST have at least one happy-path test and one error-path test.
• The help action must be tested to ensure discoverability stays accurate.

Architecture Boundary Tests

Architecture boundary tests in backend/tests/test_architecture.py enforce layer dependency rules using Python's AST module:

• Domain must not import from application, infrastructure, or api.
• Infrastructure must not import from application or api.
• API routes (api/routes/) may only import from infrastructure.database (for get_session); all other infrastructure.* imports are forbidden — including infrastructure.persistence.*, infrastructure.market_data.*, and infrastructure.external.*.

Any new module must not violate the allowed import directions. Run make test to verify boundaries have not regressed.