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Why is Regression Testing Important?

regression testing over an infinity to symbolize testing

Regression testing is an integral part of the software development life cycle. It often comes up when companies are looking to prioritize scalability. Growth potential aside, why is regression testing important? The following article will serve as a beginner’s guide to regression testing — from definition to implementation.

What is regression testing?

Regression testing has several uses, but its primary function is to test software that has recently undergone changes. It helps software developers determine whether or not a system can handle changes without compromising efficiency. For example, general function regression testing measures all areas of the software to ensure features and functionalities have remained unaffected by code or program adjustments. A few additional types of regression testing include:


  • Bug regression. This type of regression testing confirms the successfulness of patches or fixes to defects.

  • Conversion testing. Conversion testing validates the state of an application after it’s been transported to another platform.

  • Build verification. Testers use small, sequential testing to confirm whether or not a build has been irreparably damaged. Usually, this type of regression testing is used to determine whether a build should be fixed or rejected. 


Key Takeaway:

Regression testing helps developers find out whether they can introduce new code without disturbing existing functionality. 

Why is regression testing important?

Think about how often your most frequently used applications update. Now imagine that each time these updates occurred, key functionalities failed. Why is regression testing important? Because it allows developers to make continuous improvements to applications without disturbing the end user's experience. In addition to validating the functionality of new code, it ensures its compatibility with existing features.

When should regression testing be done?

The next question in line after “why is regression testing important?” is typically “when should I use it?” Utility varies from project to project, but regression testing is generally the most useful in the following scenarios:

  • Implementing new code

  • Making changes to old code

  • When an application is ported to another platform

  • Addressing program bugs

  • Fixing performance issues

How are regression tests performed?

Regression testing can be performed on the entire group of modified applications or in partial sections. Typically, regression test cases must be executed multiple times to ensure validity. For this reason, testers automate regression testing wherever possible. The regression testing process can be broken down into three steps:

Step 1

Determine which test cases the quality assurance (QA) team plans to repeat. Make sure the test cases you choose verify the main functions of the system as well as more complex cases like event sequences. Areas in the system that are vulnerable to frequent updates or code changes are the best candidates for regression testing. 

Step 2

Select your testing tools. Depending on which element of the system you’re testing, your test tools will vary. For example, API testing tools allow the tester to set input criteria and observe output performance. Functional testing tools help developers test and report defects within individual components of a program. To test particular code portions, unit testing tools allow you to single out individual functionalities within the larger application. 

Step 3

Configure and execute. Before executing your tests, configure a testing environment that will be isolated from updates or other alterations throughout the testing process. This database will protect your test cases from unnecessary interruptions that can lead to the corruption of test cases. 

Automating Regression Testing

Due to the repetitive nature of regression testing, manual testers should prioritize conserving their time and resources with automation. A general rule of thumb to follow when prioritizing test cases for automation is that it should eliminate the need for human intervention in mundane tasks. Repeat test cases that don’t require human judgment can and should be automated. Conversely, complexities like GUI event sequences should remain the responsibility of manual testers.