Fastapi Test Scaffold And Writer

Fastapi Test Scaffold And Writer

Overview

Generate pytest configuration, fixtures, and example tests for FastAPI apps with unit/integration/e2e layers. Keep tests fast, deterministic, CI-friendly, and offline by default for unit tests.

Inputs

Accept one JSON object with the schema provided by the user prompt. Treat missing optional fields as disabled. If endpoints_spec is empty, still scaffold config + fixtures + placeholder tests.

Workflow

1. Inspect project root

• Resolve project_root to a real path.
• Read existing pyproject.toml or pytest.ini and avoid clobbering custom settings.
• Detect existing tests/ structure and merge rather than overwrite.

2. Resolve FastAPI app

• Import via app_import_path.
• If import fails, scan common files (main.py, app.py, src/main.py) for a FastAPI() instance and report the best guess in comments.

3. Create or update pytest config

• Prefer pyproject.toml when preferences.use_pyproject_toml is true and no config exists.
• Ensure: testpaths=tests, addopts=-ra -q, strict-markers=true, markers: unit, integration, e2e, slow.

4. Create tests layout

• tests/conftest.py with shared fixtures.
• tests/unit/, tests/integration/, tests/e2e/ with feature-focused files.

5. Build fixtures

• app fixture importing app_import_path.
• client fixture using httpx.AsyncClient + ASGITransport.
• auth_headers fixture (stub) for dependency overrides.
• Monkeypatch fixtures for external calls (HTTP/DB/Redis) using monkeypatch or respx if installed.
• Optional deterministic fixtures (time/uuid) only if needed by specs.

6. Generate tests per endpoint_spec

• Unit tests: request validation (422), success (200) with external calls mocked, auth failure tests (401/403) via dependency overrides.
• Integration tests: DB roundtrip using TEST_DATABASE_URL; Redis set/get TTL if enabled.
• E2E tests: minimal smoke endpoint call using real dependencies; allow external LLM mock if preferences demand it.

7. CI output

• If ci.provider=github_actions, generate .github/workflows/tests.yml with unit/integration jobs; include service containers when integration_tests_use_docker is true.
• Otherwise, create docs/ci_test_commands.md with run commands.

Test Conventions

• Use pytest-asyncio for async tests.
• Use httpx.AsyncClient with ASGITransport (never spawn uvicorn).
• Unit tests must be offline and fast; mock outbound HTTP and DB/cache clients.
• Use app.dependency_overrides for auth/rate-limit dependency toggles.
• Keep fixtures small, documented, and deterministic.

Output Format

Return:

1. A short "plan" section.
2. A diff-like file list with full contents for each created/modified file.
3. A final summary listing created/modified files and pytest commands:
   • pytest -m unit
   • pytest -m integration
   • pytest -m e2e

Do not add extra explanation beyond what is needed to apply changes.