A Few Things I Wish I'd Known Earlier About Unit Testing

Things That Make More Sense in Practice

A good unit test should be fast, independent of other tests, and repeatable — producing the same result every time it runs. Using mocks and stubs in unit tests lets you simulate external dependencies, like a database, instead of calling them for real.

Why They Matter

A unit test checks the smallest testable piece of code — usually a single function or method — in isolation from the rest of the system. Tutorials often gloss over points like these, but they make a real difference on an actual project.