Validation Phase - System Testing - Regression Testing

The process of regression testing is simple i.e the test cases that have been prepared can be used and the expected results are also known. If the process is not automated it can be very time consuming and tedious operation. Some of the tools that are available for regression testing are:
- Record and Playback tools - In this, the previously executed scripts can be re-run to verify whether the same set of results are obtained. e.g. Rational Robot.

The end goals of regression testing are :
- to ensure that the unchanged system segments function properly.
- to ensure that the previously prepared manual procedures remain correct after the changes have been made to the application system.
- to verify that the data dictionary of data elements that have been changed is correct.

Most of the time the testing team is asked to check the last minute changes in the code just before making a release to the client, in this situation the testing team needs to check only the affected areas.
In short, regression testing should get the input from the development team about the nature and amount of change in the fix so that the testing team can first check the fix and then the affected areas.
Regression testing is the testing in which maximum automation can be done. The reason being the same set of test cases will be run on different builds multiple times. But then, the extent of automation depends on whether the test cases will remain applicable over the time. In case, the automated test cases do not remain applicable for some amount of time then test engineers will end up in wasting time to automate and don not get enough out of automation.