What does regression testing verify?

Regression testing is a type of software testing that ensures that recent changes, such as enhancements or bug fixes, do not adversely affect the existing functionality of the application. The primary goal of regression testing is to verify that previously developed and tested software still performs after a change has been made.

When new features are introduced or modifications are made, there's always a risk that these changes could unintentionally disrupt existing functionalities. Therefore, regression testing specifically focuses on validating that the software behaves as expected and that the previously functioning features remain unaffected by the new code. This maintains the integrity of the software and assures that users can continue to rely on its established functionalities while new features are rolled out.

This emphasis on ensuring existing functionalities are intact distinguishes regression testing from other testing types, which might focus more on testing new implementations, performance improvements, or compatibility issues.