Software developers modify and make changes to their software all the time. The problem is that every change or addition they make could lead to unexpected consequences. Because of this, software developers must continuously test their software to ensure that the new code added or the modifications made did not introduce bugs or lead to the failure of the software. This type of testing is known as regression testing.

Regression Testing: A Deeper Look

Regression testing uses tests that ensure that code alteration did not cause breakage or introduce errors and bugs into software. It also ensures that previously-fixed bugs do not come back once the alterations are done. Although software developers might not want to run these tests every time they make a change to their code, they understand that even the smallest changes, some that may even seem insignificant, can cause a cascade of issues that are completely unrelated to the new alterations made.

Regression tests not only check that the new alterations and added code performs as expected but also check that it has not caused problems in any area of the software that previously worked well. Because software developers now understand the value of regression tests, especially when working with large or legacy codebases, they are using automated regression tests. This allows them to identify any errors or bugs as soon as they are introduced. This way, the software developer can fix the errors and bugs quickly before they move forward.

Regression Vs. Retesting

There is some confusion about retesting and regression testing. Some companies test their application to see if a specific code change works as expected. This is retesting. Regression testing ensures the entire system, including the added code changes, works as expected. This is why regression testing has a much broader scope than retesting. Also, retesting can be included as one of the regression tests.

Major Challenges to Regression Testing

A major challenge to regression testing is the increase in the amount of time it takes to complete the tests as the codebase becomes larger. To reduce total testing time, companies are encouraged to evaluate their current regression testing strategies and methodologies. This includes examining how they are doing the tests, the design of their regression test cases, the context within which the tests are run as well as finding areas of improvement in the testing methodologies.

When trying to decrease the amount of time these tests take, developers can try to minimize the test suite. However, this introduces another challenge because they now have to think about maximum test coverage while remaining inside a reasonable test suite.

Lastly, identifying the optimum frequency of regression tests can be challenging. Does a developer do a test after every update, after several bugs have been fixed, or after new code is committed to a repository?

Regression testing is an important part of the software development and maintenance cycle. Developers have to be sure that the changes they introduce to a codebase do not lead to a cascade of unintended consequences.