Assignment 1 — Build a Full Test Suite for a FastAPI App#

Goal:#

Create a complete test suite for a small FastAPI application. Students will practice:

Unit tests
Async API tests
JWT authentication tests
Mocked async DB testing with SQLAlchemy
Applying a professional test folder structure

Assignment Description#

You are given a FastAPI application (from Unit 06) that contains:

CRUD endpoints for users
Async SQLAlchemy database connection
JWT-protected endpoint
Helper utilities

Your task is to create a production-quality test suite using:

pytest
pytest-asyncio
httpx.AsyncClient
PyJWT
Mocked in-memory SQLite async DB
Test folder structure best practices

Requirements#

1. Create the test folder structure#

Your project test can be referred to as below (depending on the structure of Unit 06)

tests/
 ├── conftest.py
 ├── factories/
 │    └── user_factory.py
 ├── utils/
 │    └── jwt_helpers.py
 ├── unit/
 │    └── test_helpers.py
 ├── integration/
 │    ├── test_users.py
 │    └── test_auth.py
 └── e2e/
      └── test_full_flow.py

2. Write tests for the following:#

A. UNIT TESTS (no FastAPI, no DB)#

Example: math helpers, pure functions, etc.

B. ASYNC INTEGRATION TESTS#

Using AsyncClient:

Test async GET and POST endpoints
Test error paths (404, 400, etc.)

C. MOCKED ASYNC SQLALCHEMY DB TESTS#

Using an in-memory SQLite database.

Example tasks:

Mock DB session in conftest.py
Test database CRUD operations via API
Validate isolation between tests

D. JWT AUTH TESTS#

Test the /secure endpoint with:

Valid token
Expired token
Missing authorization header
Invalid/malformed token
Wrong secret-key token

3. End-to-end Test#

Simulate a full workflow:

Create a user
Authenticate (or generate a token)
Access a secured resource
Fetch user data from DB

Expected Output#

A fully working test suite that can run using:

pytest -v

Grading Criteria#

Category	Points
Folder structure	10
Unit tests	10
Async API tests	20
Mocked DB tests	25
JWT tests	25
Code quality & readability	10

Total: 100 points