Regression Testing refers to the type of software testing to make sure that a recent change in program or code has not adversely impacted the existing features.

In other words, Regression Testing is a full or partial selection of formerly performed test cases which are re-performed to assure existing functionalities work fine. During regression testing, new software bugs or regressions may be exposed. Sometimes a software change impact investigation is performed to find out what areas could be affected by the purposed changes.

It can be carried out to test a system efficiently by systematically picking out the appropriate minimum set of tests required to cover a particular change adequately.