Python FastAPI Tutorial (Part 17): Testing the API - Pytest, Fixtures, and Mocking External Services

In this Python FastAPI tutorial, we will learn how to test our FastAPI application using Pytest, HTTPX's AsyncClient, and mocking tools like Moto. We'll start by setting up our test structure and fixtures in conftest.py, including a transactional rollback pattern for fast and isolated database tests. From there, we'll write tests for our API routes covering authentication, CRUD operations, file uploads, ownership checks, and background tasks. We'll also learn how to mock external services like AWS S3 and email sending, so our tests don't depend on real infrastructure. By the end of this video, you'll have a solid set of real-world testing patterns that you can apply to your own FastAPI projects. Let's get started... The code from this video can be found here: https://github.com/CoreyMSchafer/FastAPI-17-Testing Full FastAPI Course: https://www.youtube.com/playlist?list=PL-osiE80TeTsak-c-QsVeg0YYG_0TeyXI ✅ Support My Channel Through Patreon: https://www.patreon.com/coreyms ✅ Become a Channel Member: https://www.youtube.com/channel/UCCezIgC97PvUuR4_gbFUs5g/join ✅ One-Time Contribution Through PayPal: https://goo.gl/649HFY ✅ Cryptocurrency Donations: Bitcoin Wallet - 3MPH8oY2EAgbLVy7RBMinwcBntggi7qeG3 Ethereum Wallet - 0x151649418616068fB46C3598083817101d3bCD33 Litecoin Wallet - MPvEBY5fxGkmPQgocfJbxP6EmTo5UUXMot ✅ Corey's Public Amazon Wishlist http://a.co/inIyro1 ✅ Equipment I Use and Books I Recommend: https://www.amazon.com/shop/coreyschafer ▶️ You Can Find Me On: My Website - http://coreyms.com/ My Second Channel - https://www.youtube.com/c/coreymschafer Facebook - https://www.facebook.com/CoreyMSchafer Twitter - https://twitter.com/CoreyMSchafer Instagram - https://www.instagram.com/coreymschafer/ #Python #FastAPI