Definitions of regression testing

1. Regression testing is any type of software testing which seeks to uncover regression bugs. Regression bugs occur whenever software functionality that previously worked as desired, stops working or no longer works in the same way that was previously planned. Typically regression bugs occur as an unintended consequence of program changes.
2. The selective retesting of a software system that has been modified to ensure that any bugs have been fixed and that no other previously working functions have failed as a result of the reparations and that newly added features have not created problems with previous versions of the software.
3. Regression testing is the process of testing changes to computer programs to make sure that the older programming still works with the new changes.
4. Re-testing of a previously tested product following modification to ensure that faults have not been inadvertently introduced to unchanged functionality.
5. Part of the test phase of software development where, as new modules are integrated into the system and the added functionality is tested, previously tested functionality is re-tested to assure that no new module has corrupted the system.