Day 18 — FastAPI Testing & Code Cleanup

Day 18 of #60DaysOfPython — Took the Day 17 FastAPI + SQLAlchemy project and refactored it for production readiness: fixed bugs, cleaned up code quality, and proved every endpoint works correctly with a full pytest test suite covering all user roles and edge cases.

What Changed from Day 17

Part A — Cleanup

• Renamed Exceptions.py → exceptions.py (PEP 8: lowercase module names)
• Fixed all imports pointing to the old filename
• Replaced vague error messages like "do not have Permission " with clear, professional ones
• Removed dead code and redundant variable assignments
• Fixed deprecated APIs: declarative_base, utcnow, Pydantic class-based Config
• Added correct status_code=201 to POST endpoints that create resources

Part B — Test Suite

• tests/conftest.py — shared test DB, fixtures, and helper functions
• tests/test_auth.py — register and login flows
• tests/test_users.py — /me, /dashboard, role protection, delete account
• tests/test_courses.py — create course, list courses, auth protection

Test Results

17 passed in 20.48s

Endpoints Tested

Endpoint	Method	Test Coverage
/register	POST	Success 201, duplicate email 400
/login	POST	Valid credentials 200, wrong password 401
/me	GET	Valid token 200, no token 401
/dashboard	GET	Teacher 200, student 403
/users/{id}	GET	Own profile 200, other user 403
/users/{id}	DELETE	Own account 200, other account 403
/courses	POST	Teacher 201, student 403, no token 401
/courses	GET	Logged in 200, no token 401

Tech Stack

• FastAPI — API framework
• SQLAlchemy — ORM with SQLite
• Pydantic v2 — request/response validation
• python-jose — JWT token generation and verification
• passlib + bcrypt — password hashing
• pytest + httpx2 — test runner and HTTP client

Project Structure

day18-fastapi-testing/
├── main.py              # all route definitions
├── auth.py              # JWT logic and role dependencies
├── models.py            # SQLAlchemy User and Course models
├── schemas.py           # Pydantic request/response schemas
├── database.py          # DB engine and session setup
├── exceptions.py        # custom HTTP exceptions
├── pagination.py        # reusable pagination dependency
├── requirements.txt
└── tests/
    ├── conftest.py      # shared fixtures and test DB
    ├── test_auth.py
    ├── test_users.py
    └── test_courses.py

Setup & Run

pip install -r requirements.txt
uvicorn main:app --reload

Run Tests

pytest -v

Part of

#60DaysOfPython — rebuilding to professional software development, one project a day.