Validation Phase - System Testing - Regression Testing

Regression testing is used to test or check the effect of changes that are made in the code. Most of the time the testing team is asked to check 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, for regression testing, the testing team should get the input from the development team about the nature or amount of change in the fix so that the testing team can first check the fix and then the side effects of the fix.

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, the extent of automation depends on whether the test cases will remain applicable for some amount of time, test engineers will end up in wasting time to automate with minimal results.

Regression testing is re-testing unchanged segments of application. It involves re-running tests that have been previously executed to ensure that the same results can be achieved currently as were achieved when the segment was last tested. The selective re-testing 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 newly added features have not created problems with previous versions of the software.

Regression testing is initiated after a programmer has attempted to fix a recognized problem or has added source code to a program that may have inadvertently introduced errors. It is a kind of quality control measure to ensure that the newly modified code still complies with its specified requirements and that unmodified code has not been affected by the maintenance activity.

During regression testing, following activities are performed:
- Re-running of previously conducted tests.
- Reviewing previously prepared manual procedures.
- Comparing the current test results with the previously executed test results.