Code quality and testing Build step five: before you ship your app, make sure it works and keeps working. Three lessons: fast unit tests, integration tests against a real database, and clean code you refactor safely.
Lessons 0 Overview Build step five: before you ship your app, make sure it works and keeps working. Three lessons: fast unit tests, integration tests against a real database, and clean code you refactor safely. 1 Unit tests Why we write tests, the shape of a good test (arrange, act, assert), pytest and unittest, edge cases, and mocks for slow or external parts. 2 Integration tests When each piece works alone and they fail together: testing code against a real database, testing a whole HTTP API, the test pyramid, and setting up and cleaning test data. 3 Clean code and refactoring Names that tell the truth, small functions with one job, less nesting with early returns, removing duplication carefully, and refactoring in small steps guarded by tests. 4 Wrap-up and resources The takeaways and glossary of this track.