Business Definition: The purpose of this testing is to verify that recent code changes haven't altered or destroyed the already existing functionality of the system. Regression testing is responsible for confirming the overall stability and functionality of the existing features. Technical Definition: Re-running functional and non-functional tests to ensure that previously developed and tested software still performs, as designee following a change. Changes that require regression testing include bug fixes, software enhancements, configuration changes, as well as substitution of electronic components. As regression test suites tend to grow with each found defect, test automation is frequently involved.