What is Regression Testing? Definition & Test Cases

Regression testing is a suite of tests designed to detect defects in areas of an application that have already been tested. This is done not to make sure that there are no bugs, but rather to find and fix regression errors.

Regression errors are the same bugs, but they do not appear when writing a code, they appear when a new software build is added to an existing build or other bugs are fixed, which caused new defects to appear in an already tested product. So the goal of regression testing is to make sure that fixing some bugs or adding a new build did not cause new bugs.

There are several types of regression tests:

• Verification tests. They are carried out to check the fix of a previously discovered bug.
• Build Verification Test. Contains the principles of smoke testing and build testing: testing the main functionality of the program in each new build.
• Regression testing itself is a re-run of all tests that were written and done before. They are performed using already existing test cases, regardless of whether bugs were found or not.
• Testing fixed old build bugs in a new build. This is done to check if the update of the build has not triggered old defects.

Main points of regression testing:

• This type of testing is done in each new build.
• You need to start with build verification tests.
• Checking for fixed bugs.
• Regression testing, in general, does not cover the entire application, but only those areas that in one way or another were affected by the changes in the build.

After that, bugs that have already been closed are tested again.

When is Regression Testing Reccomended?

1) Regression testing is recommended to be performed several times (3 – 5 times). Test automation is actively used in this type of testing to save time and, perhaps, to get out of routine.

2) For conducting the final regression testing, tests are selected according to the priority which depends on the largest number of errors found.

Regression testing is also actively used in extreme programming and a very popular software testing type.