Testing with database in FastAPI - Cheat Sheet & Quick Revision

Recall & Review

beginner

Why do we use a separate test database when testing FastAPI applications?

Using a separate test database keeps test data isolated from real data. This prevents accidental data loss or corruption and allows tests to run safely without affecting the live system.

intermediate

What is the purpose of using SQLAlchemy's session rollback in tests?

Session rollback resets the database state after each test. This ensures tests do not affect each other by leaving data behind, keeping tests independent and reliable.

beginner

How does the TestClient in FastAPI help with testing endpoints?

TestClient simulates HTTP requests to your FastAPI app without running a real server. It lets you test routes and responses quickly and easily in your test code.

intermediate

What is a fixture in testing with pytest and why is it useful for database tests?

A fixture sets up and tears down resources needed for tests, like a test database session. It helps keep tests clean and avoids repeating setup code.

advanced

Explain the role of dependency overrides in FastAPI testing with databases.

Dependency overrides let you replace real dependencies (like the database session) with test versions. This allows tests to use a test database instead of the real one.

What is the main reason to use a test database in FastAPI testing?

A To keep test data separate from production data

B To speed up the application in production

C To avoid writing tests

D To make the database bigger

Using a test database keeps test data isolated, preventing interference with real data.

Which FastAPI tool allows you to simulate HTTP requests in tests?

A DependencyInjector

B SessionRollback

C TestClient

D DatabaseFixture

TestClient lets you send fake HTTP requests to your FastAPI app during tests.

What does a pytest fixture typically do in database testing?

A Runs the production server

B Sets up and cleans the test database session

C Deletes the database permanently

D Creates user interface elements

Fixtures prepare and clean resources like database sessions for tests.

Why is session rollback important after each test?

A To speed up the database

B To close the database connection

C To save data permanently

D To reset database changes and keep tests independent

Rollback undoes changes made during a test so other tests start fresh.

How do dependency overrides help in FastAPI database testing?

A They replace real database sessions with test sessions

B They speed up the database queries

C They disable the database

D They create new API routes

Dependency overrides let tests use a test database instead of the real one.

Describe the steps to set up a test database session in FastAPI tests.

Think about how to isolate tests and keep them independent.

Explain why dependency overrides are crucial when testing FastAPI apps with databases.

Consider how FastAPI injects dependencies and how tests can change that.