Testing is the practice of verifying that software behaves as expected. It includes unit tests, integration tests, end-to-end tests, and performance tests. Testing ensures correctness, prevents regressions, and increases confidence when deploying changes. Many development workflows integrate automated testing into CI/CD pipelines.
Why it matters
Without testing, bugs slip into production, features break unexpectedly, and development slows due to uncertainty. Testing helps maintain software quality, reduces risk, and supports long-term maintainability.
Examples
Writing unit tests with Jest or PyTest, performing integration tests on an API, or running automated browser tests. Lessons like What Is Testing? teach foundational methods.