api-testing

name	api-testing
description	API testing patterns for FastAPI endpoints using pytest and httpx

API Testing Patterns

Project Test Setup

• Test client via httpx.AsyncClient with app from api.main
• Fixtures in tests/conftest.py (TEST_MODE=true, mock DB)
• Always use --no-cov flag: .venv\Scripts\python.exe -m pytest --no-cov

Running Tests

# All API tests
.venv\Scripts\python.exe -m pytest tests/ --no-cov -v

# Single test file
.venv\Scripts\python.exe -m pytest tests/test_premium_upgrade.py --no-cov -v

# Single test
.venv\Scripts\python.exe -m pytest tests/test_rate_limiting.py::test_login_rate_limit --no-cov -v

# By marker
.venv\Scripts\python.exe -m pytest -m unit --no-cov

Test Structure

import pytest
from httpx import AsyncClient

@pytest.mark.asyncio
async def test_endpoint_name():
    async with AsyncClient(app=app, base_url="http://test") as client:
        response = await client.post(
            "/api/endpoint",
            json={"key": "value"},
            headers={"Authorization": "Bearer test_token"}
        )
        assert response.status_code == 200
        data = response.json()
        assert data["success"] is True

Auth Patterns

• Use TEST_MODE headers: {"X-Test-User-ID": "123"}
• Or mock get_current_user dependency
• Never hit real auth in tests

Rate Limit Testing

# SlowAPI stores limits in limiter._route_limits dict
key = "module.path"  # e.g., "api.routers.user.login"
limits = app.state.limiter._route_limits.get(key)
assert limits is not None

DB Mock Patterns

• Use pytest.mark.unit for no-DB tests
• Use pytest.mark.integration for real DB tests
• Mock DB functions for unit tests of business logic

What NOT to Do

• Don't run tests/test_agent_scenarios.py (pre-existing, broken)
• Don't use --cov flag (breaks SlowAPI inspect.signature)
• Don't run all tests/ files together (hangs on external service tests)
• Run only our 16 test files explicitly