1. What is regression testing? Regression testing is a type of testing that ensures there are no defects/issues in exiting functionality because of new change.

2. What types of changes require regression testing Bug fixes After developer changes the code to fix the bug, regression testing is performed to make sure that there is no impact on exiting functionality due to recent code change. New functionality When new functionality is develop,regression testing is performed that new changes don’t impact exiting functionality. Technological changes in system If any technical changes in system like software upgrade, regression testing is performed to make sure that those changes doesn’t impact exiting functionality.

3. Why regression testing is important ? Regression testing ensures that when application is moved to production all the existing functionalities have been tested thoroughly and they work as per the requirements. It avoids any loopholes introduce in the system because of new changes It avoids any new issues or design flaws introduced by the new changes

4. Example for regression testing New functionality Online shopping card currently accepts payments only by credit card. New functionality is added to accept gift cards. Regression testing should be performed in all existing functionality which used to take credit card as payment to ensure that new payment type functionality is not impacting functionality of payment with credit cards. Bug fix Application takes user’s address details, address details are limited to country USA. There was a defect found in system which allowed user to enter numeric values in address. After developer fixes that address, regression testing should run all the test cases for validating and submitting address details. Technical changes Application security software is upgraded to new version. All the functionality related to login, security should be re-tested to ensure it works with new technological changes.