The Types of Testing

Overview

There are several types of testing in programming, each on a different level of complexity and size. Unit tests stand on one side of the spectrum. They check one isolated piece of code, a class, or a function. They’re very fast and almost always automated. On the other side of the spectrum, end-to-end tests run against entire applications. They’re slow and, more often, manual. Between these two levels, we have component and integration tests, which are a level up from the isolated unit tests but still only verify part of the system, mocking some applications or removing them from the equation. Smoke tests might be seen as another category. They work with a real system, and their goal is to give quick feedback, alerting us if even basic functionality isn’t working anymore, that is, if there’s proverbial smoke coming from the system.