Regression testing is a type of software testing that verifies that software previously developed and tested still performs correctly after it was changed or interfaced with other software. Changes may include software enhancements, patches, configuration changes, etc.

• Rerunning the previously conducted tests.
• Comparing current results with previously executed test results.

This is a continuous process performed at various stages throughout the software testing life cycle. A best practice is to conduct regression test after the sanity or smoke testing and at the end of functional testing for a short release.