As software evolves through performance enhancements, bug fixes, and feature updates, even the smallest code changes can ripple through the system, introducing unexpected issues. Maintaining software quality therefore isn’t just about adding new functionality, it’s about ensuring that existing features remain stable and reliable.
Regression testing involves re-evaluating previously tested functionalities to ensure that recent code changes have not impacted existing features. By systematically running a suite of tests after updates, teams can quickly identify regressions, unintended side effects like broken features, performance degradation, or security vulnerabilities. This continuous validation helps maintain the integrity of the application while accelerating development cycles.
In this blog, we’ll cover the basics of regression testing including how it works, an example of regression testing in the real world, and why implementing it could be beneficial for your business.
When is Regression Testing Necessary?
Below are some common cases in which regression testing is needed:
- Adding new features – Regression testing is used to validate that pre-existing features continue to operate seamlessly, and risks of a downtime are mitigated.
- Bug fixes – Regression testing is used to verify that code adjustments to fix defects do not affect other components in the application.
- Optimizing the code – Regression testing guarantees that optimizing the code will enhance the application without impacting other functionalities.
Example of Regression Testing in the Real World – Amazon
By using regression testing, you can confidently implement changes to your software while maintaining the user experience across various functionalities.
Take Amazon.com as an example. In a normal day, Amazon’s e-commerce platform processes millions of transactions, making seamless performance paramount to the company’s operations. Therefore, when a new feature is added to the homepage such as a “Prime Day” exclusive offer, it is vital to make sure that such an addition does not disrupt any of the existing functionalities like search, cart checkout, or payment processing. To verify this, a regression test suite is needed to confirm that all other components continue performing as expected.
If this test fails and reveals that the “Checkout” button is unresponsive or leads to a broken link, it would be flagged as a bug. Developers would then prioritize fixing this issue to prevent loss of revenue and damage to the Amazon’s reputation.
How to Implement Regression Testing Effectively
The procedure to implement regression testing is similar to other testing methods. Each time the application undergoes code adjustments; the following steps are taken:
- Unit-level regression tests are performed to validate the modified code alongside any other tests written to cover new or changed functionality.
- Then, the new code is merged and integrated to create a new build of the application under test.
- Next, smoke tests are executed for assurance that the build is good before any additional testing is performed.
- Once the build is verified, integration tests are performed to validate the interaction between units of the application with each other and with end services like databases.
- After that, depending on the size and scope of the released code, either a partial or a full regression is scheduled.
- Defects are then reported back to the development team.
The Different Types of Regression Testing
Regression testing comes in different forms, each one serving a specific purpose. Here are some common types:
- Corrective regression testing – This type focuses on verifying that specific fixes made to the application have been successfully resolved without introducing problems.
- Retest-all regression testing – This type involves re-running all the test cases in the test suite to ensure that the entire application is still functioning correctly.
- Selective regression testing – As the name indicates, this type of test is only a subset of the test cases that are most likely to be affected by the recent changes, reducing the effort and cost of testing.
- Progressive regression testing – This type is used when there is an update on the software specifications.
- Complete regression testing – This type is performed when multiple changes have been made to the software. It involves testing the entire application to ensure overall stability.
- Unit regression testing – Focuses on testing individual units or components of the software to ensure no new defects are introduced at the unit level.
Benefits of Regression Testing
By incorporating regression testing into the development process, organizations can guarantee that their software and applications remain robust and reliable, even as it evolves. Here’s are the main advantages of regression testing at a glance:
- Preserving functionality – Protecting existing features from unintended outcomes of code changes.
- Boosting confidence in new releases – Providing assurance for successful new releases and updates.
- Enhancing quality – Detecting and resolving defects early.
- Improving efficiency – Implementing automation which accelerates testing, minimizes errors, and lowers development effort.
- Ensuring user satisfaction – Delivering a consistent and reliable user experience.
Discover Regression Testing with Q-Pros
In practice, effective regression testing often involves a combination of automated and manual approaches. Automated testing speeds up the process, enabling rapid feedback and more frequent deployments, while manual testing adds context and exploratory insights where needed. Together, these methods help balance speed and thoroughness, ensuring both new and existing features meet quality standards.
Implementing robust regression testing practices can yield significant business benefits. It reduces the risk of production defects, enhances user satisfaction by preventing disruptive issues, and supports faster, more confident releases. Our experienced testers use the latest techniques and industry-leading test automation tools to execute regression tests efficiently and ensure a smooth, reliable, and efficient process that enhances product quality, reduces risks, and saves time and resources for your development team.
