A Complete Guide to Regression Testing

Timothy Joseph
Timothy Joseph | April 27, 2021
A Complete Guide to Regression Testing

One step forward, two steps back. That’s what you can expect when your QA strategy doesn’t include software regression testing.

The reason why is simple. Consumers like changes and upgrades to their favorite software products, but they also like consistency. In their eyes, advancement is a nice-to-have, but the ability to interact with your application easily is a must.

It doesn’t matter how many cool features you add or how drastically you change the UI. If expected functionality no longer exists, then your end users won’t continue to use your product.

See why so many QA teams don’t take the importance of regression testing lightly? It’s up to your testers to make sure that expectation is delivered from one deployment to the next.

This guide answers all your questions about regression testing, including:

  • What is regression testing?
  • What types of regression testing should I perform?
  • When should I perform manual or automated regression testing?
  • How do I overcome regression testing challenges?
  • What are the best regression testing tools?

What Is Regression Testing?

In QA testing, software regression testing is the practice of validating the functionality of existing features within your software application. QA teams perform various types of regression testing with each new code change to ensure that the system still functions as expected. A strong QA strategy incorporates both manual and automated regression testing to confirm that the new changes do not cancel out or negatively impact previously established functionality.

The importance of regression testing can’t be disputed. It’s your QA team’s duty to manage risks and prevent bugs from being released into production—and regression testing is designed to do just that. By finding defects or system malfunctions caused by the new code, your team can repair the damage before market launch.


When To Implement Regression Testing

Now that you understand what regression testing is, it may be unclear as to when it should be performed within your QA strategy. In fact, many teams face regression testing challenges when regression tests aren’t performed regularly throughout the development cycle.

Consider performing software regression testing anytime the following events occur within your project:

  • Introducing a new feature: When developers add new code, their attention isn’t always focused on its compatibility with existing code. With the assistance of regression testing tools, QA engineers can uncover any possible issues within the software before deployment. The importance of regression testing can be seen by how many issues within the updated code are discovered during the QA process.
  • Upgrading an existing feature: It’s common for developers to receive a request to enhance existing product functionality based on consumer feedback. When business requirements don’t address how specific features should still function, your new code may accidentally damage or remove existing functionality from the system. Through automated regression testing, your QA testers can check whether or not current functionality still performs as expected.
  • Updating your UI or introducing a new integration: When presenting a new experience within your product, your QA team should test for more than usability. The new design or integration may unintentionally alter how previous feature functionality performs, so it’s up to your QA team to execute all types of regression testing in order to verify previous product functionality.

Types of Regression Tests

Regression testing includes multiple tactics for detecting application defects? To get the most value from each regression test, it’s worth strategizing how to perform it before execution. We recommend including these types of software regression testing within your QA strategy.

  • Corrective Regression Testing: This type of regression testing verifies that all feature functionality works as intended, even when there are no new changes to the code check. Testers can reuse these test cases across development cycles.
  • Retest-All Regression Testing: The entire system is retested during this type of regression testing to confirm that there are no defects to the current code with the new changes in place. This approach is recommended when extensive updates and revisions are introduced within the application.
  • Selective Regression Testing: Testers check how the new code impacts the current code. These test cases can be reused across development cycles.
  • Progressive Regression Testing: This type of testing is ideal when there are minor code changes within the system. Through new test cases, testers confirm that no previous features are compromised within the updated code.
  • Unit Regression Testing: QA engineers review the code as a unit, verifying that all resultant dependencies are blocked out during testing. This type of regression testing centers is best for validating functionality for key features or components already in the application.

Regression Testing Tools

There’s no shortage of tools for regression testing on the market. But, it’s key to choose the right tool for your team so that they can perform software regression testing smoothly and efficiently. When researching your options, we recommend considering these regression testing tools.

  • Selenium: Considered one of the best automated tools for regression testing web applications, Selenium is designed for building powerful, browser-based test cases. This open source tool offers cross-environment support across operating systems and browsers as well as compatibility across multiple programming languages and testing frameworks.
  • IBM Rational Functional Tester: This tool specializes in automated function testing within the regression testing process and supports data-driven and GUI testing. IBM Rational Functional Tester features a call script capability for creating and running regression tests and supports a variety of web-based apps including Java, Ajax and NET.
  • TestComplete: Automate your regression tests easily and quickly with TestComplete. This testing tool integrates well with other defect tracking tools, executes parallel regression tests with automated builds and automatically schedules regression tests without manual intervention.
  • Testimony: Engineered specially for SAP software, this tool reinvents regression testing by eliminating the creation and maintenance of test scripts. Testimony can automatically create an up-to-date test library, perform system-wide tests within days and run tests beyond the user interface, including BAPIs and batch jobs.
  • Watir: This open source tool uses the Ruby programming language for automating regression testing. Watir—an abbreviation for Web Application Testing in Ruby—offers excellent browser interaction capabilities, cross-platform support and the ability to design compliant, maintainable automated regression tests.

Benefits of Regression Testing

Regression testing challenges only occur when a strong QA strategy isn’t in place. After calculating the ROI of regression testing, it’s easy to see why so many QA teams include running regression tests for their projects. When implemented correctly, your team can enjoy these benefits across development cycles.

  • Identify bugs created by new software additions or adjustments: Discovering a bug is just the start of the resolution process. Knowing why that bug exists within your application can help your developers devise how to fix the problem. And with software regression testing, your QA team can pinpoint which new code adjustments or additions created the issue.
  • Automation opportunities: Every minute counts during a development cycle, especially when regression tests are performed as the final testing step in QA. Fortunately, many types of regression testing can be automated to streamline your testing process, uphold testing accuracy and catch bugs sooner.
  • Compatible with integration testing: As new units of functionality are introduced into the system, integration testing can confirm that no errors are introduced. Once all new units of functionality are in the testing environment, QA engineers can confirm through regression testing that all product functionality works as intended.

Automated vs Manual Regression Testing

You can expect to run into regression testing challenges if your team doesn’t execute test cases effectively or apply the right types of regression testing to each situation. The importance of regression testing is to find defects within previously approved code changes, so knowing how to find these issues can be the difference between finding it before market launch—or not at all.

So, should your team test manually or with automation? That depends on the test case.

  • Automated regression testing: When automating the testing process, QA testers write code for the test script and use regression testing tools to perform these test cases. Your QA team should automate your software regression testing process for testing feature functionality across hundreds of product touchpoints. Automated testing is ideal for test cases focused on repetitive tasks that can be prone to human error when tested manually.
  • Manual regression testing: What is regression testing without finding bugs in your application the way a consumer would? In manual testing, human testers walk through the experience of your product to see if previous feature functionality still works. QA teams should manually perform regression testing when there are UI changes and for performing exploratory tests, which cannot be supported by automated testing.

Does your team require more help with software regression testing than this guide provides? You can choose to partner with a reliable QA services provider like QASource. Our team of testing experts specialize in both manual testing and automation testing with years of experience performing regression testing for applications across domains. We can help your team implement best practices for regression testing so that your team protects the quality of your product upon every release. Get a free quote today.


This publication is for informational purposes only, and nothing contained in it should be considered legal advice. We expressly disclaim any warranty or responsibility for damages arising out of this information and encourage you to consult with legal counsel regarding your specific needs. We do not undertake any duty to update previously posted materials.