Regression testing a black box testing technique that consists of re-executing those tests that are impacted by the code changes.

These tests should be executed as often as possible throughout the software development life cycle.

It is performed to validate the build that hasn't changed for a period of time. This build is deployed or shipped to customers.

A normal regression testing is performed to verify if the build has not broken any other parts of the application by the recent code changes for defect fixing or for enhancement. It finds other related bugs.

It tests to check the effect on other parts of the program. Regression testing produces Quality software. Validate the parts of software where changes occur.

It validates parts of software which may be affected by some changes but otherwise unrelated.

It ensures proper functioning of the software, as it was before changes occurred. It enhances quality of software, as it reduces the high risk bugs.

Regression testing is useful when there are updates expected in product. It is helpful to check overall functionality in changing situations.