How to Write Great Unit Tests in Python

Check out https://www.squarespace.com/arjancodes to save 10% off your first purchase of a website or domain using code ARJANCODES. Want to learn how to write professional, maintainable unit tests in Python? In this video, I’ll walk you through the entire process using a realistic WeatherService example—from basic testing principles to powerful pytest features like monkey patching, mocking, fixtures, and parametrization. 💡 Learn how to design great software in 7 steps: https://arjan.codes/designguide. 🔥 GitHub Repository: https://git.arjan.codes/2025/testtips. 🎓 ArjanCodes Courses: https://www.arjancodes.com/courses. 💬 Join my Discord server: https://discord.arjan.codes. ⌨️ Keyboard I’m using: https://amzn.to/49YM97v. 🔖 Chapters: 0:00 Intro 1:01 The Basics of Unit Testing 3:45 Monkey Patching 8:51 Mocking vs. Monkey Patching 12:20 Using Fixtures 14:01 Refactor for Testability 16:39 Neat Pytest Features 19:59 Best Practices for Writing Unit Tests 22:20 Final Thoughts #arjancodes #softwaredesign #python