Companies go through rigorous software testing to ensure their software is ready and error-free for its users before the software is released. But pre-launch is not the only time a company should be thinking about software testing. Regression testing is an important tool in your software testing arsenal, and knowing the basics of regression testing will help you understand exactly what regression testing is and how it helps software companies with quality assurance.

What is Regression Testing?

Regression testing is a specific kind of software testing that happens after a change, such as an update to fix a bug, is made to existing software after development. This type of testing is performed to make sure that none of the other sections of the software, which were working fine before, have “regressed” and stopped their previous functionality.

Why You Need Regression Testing

Because software code is modular and a change to one section of the code can impact the other sections it interacts with, regression testing is essential for assuring that one bug fix doesn’t accidentally create several new bugs. It’s important to have your software reevaluated with a regression test any time old code is updated or new code is added to the software. This way, you can be assured that the new changes or code will not cause problems in the areas that previously were working fine.

When to Regression Test Your Software

If you have a finished software projects that requires changes be made, either because a defect is being fixed or because you are adding a new functionality, you need to regression test your software. This also includes testing after updates are made to other softwares that your software interacts with. For example, if your software is meant to import information from a business’s CRM software and an update is made to that CRM software, that change may cause your import to result in errors, or regress.

Regression testing is especially important in an agile environment. When there are constant changes being made to interlocking sections of code, it’s especially important to make sure that the code that depends on your changes does not break down. The speed between sprints using agile development also means that these regression tests need to be carried out quickly. Because of this, it’s important that agile teams have a regression testing strategy in place right from the beginning of development, and they may even want to consider automated regression testing.

Regression Testing Methods

With agile development, here are three main approaches to regression testing that help mediate the amount of testing needed with the amount of time it has to get done: the delayed week approach, the traditional regression testing approach, and the delayed sprint approach. Each one has its pros and cons, and will require your software testing engineers to consider the goals of their regression testing strategy carefully. The traditional approach alternates sprints with end-to-end regression tests aimed at the changed code, while the delayed week and delayed sprint approaches are a way to continue making changes while regression testing at the same time.

Whatever approach you need, regression testing is a basic necessity of software quality assurance. Understanding the basics of regression testing can help you choose the right method for your software and improve the quality of its updates.