What process confirms that changes in code have not affected existing functionalities?

Regression testing is the process that confirms that recent changes or updates in the code have not negatively impacted the existing functionalities of a software application. This phase of testing is essential to ensure that new code does not introduce new bugs into existing features, replacing other testing methods or processes that primarily focus on different aspects of quality assurance.

In regression testing, previously developed and tested software components are re-examined to verify that they still perform as expected after specific changes have been made. This can involve running a suite of test cases that cover both the new features and the previously functioning features, ensuring overall software stability and performance post-modification.

While smoke testing is designed to verify that the most crucial functions of an application work correctly after a new build, it does not delve into the full spectrum of functions to assess impacts on existing features. Performance testing assesses how the system behaves under load, focusing on speed, responsiveness, and stability, rather than checking for functionality. Stress testing evaluates how the application behaves under extreme conditions, which is also not aimed at validating existing functionalities. Thus, regression testing is uniquely positioned to provide confirmation that changes have not disrupted the application’s established workings.