What does "regression testing" involve?

Regression testing involves validating that recent changes, such as new features, bug fixes, or enhancements, have not negatively impacted the existing functionalities of a software product. This type of testing ensures that previously working features continue to function as expected after any modifications are made. The primary goal of regression testing is to catch any unintended side effects resulting from changes, which is crucial for maintaining software quality and ensuring that users have a consistent experience.

In contrast, testing new features focuses solely on the functionality of those additions without regard to their impact on existing code. User acceptance testing centers around assessing the software's readiness for end users based on their requirements and is distinct from regression concerns. Lastly, testing documentation for compliance involves ensuring that the documentation meets certain standards or regulations, which is unrelated to the functionality of the software itself. Thus, the focus of regression testing is squarely on preserving the integrity of existing features amidst any changes made.