Regression Testing
March 27, 2024

What Is Regression Testing? Explained

Continuous Testing
DevOps

As you are well aware if you live in today's world, when using your iPhone or Android you encounter regular software updates that improve the functionality of your device and its applications. Hopefully, these updates have been thoroughly tested prior to deployment to ensure a seamless and uninterrupted user experience. 

It is crucial for teams releasing updates to perform comprehensive testing prior to launching the update. After all, small changes can have big consequences. 

This is where regression testing comes in. Regression testing ensures that code changes don’t break the functionality of your app or software. Regression testing also catches bugs early on in new builds. Without regression testing, it can be more difficult, time-intensive, and expensive to find defects, which can have an adverse affect on user experience and your bottom line. But what is regression testing?

This blog will provide the ultimate overview of the role of regression testing.

Related Reading: Test Smarter, Not Harder: A Guide to Efficient Testing >>

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What Is Regression Testing? 

Regression testing means software testing that verifies recent changes — either to the program or code — didn’t negatively impact the existing features of the software. Recent changes can range from fixing bugs to adding or updating features.

Software regression testing makes sure recent changes don't impact existing features. In Agile, regression testing means helping teams focus on developing (new) functionality while maintaining a stable product.

Regression testing in Agile is best done with test automation and continuous testing tools. This keeps teams focused on innovation through new features and releases. Regression testing reveals defects early in the software development process, reducing risk as well as the time it takes developers to fix defects.

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When is Regression Testing Done?

There are many conditions where regression testing is required. Some typical use cases for regression testing include:

  • New features.

  • Fixed defects that require code changes.

  • New requirements to existing features. 

  • Code optimizations.

  • The release of new software versions.

  • UI changes.

  • New third-party integrations.

Another way to help determine when regression testing should be done is based on your overall testing capacity. The Test Coverage Cube can help you better understand your organization’s testing capacity by measuring your testing depth.

Coverage cube with red squares

By measuring quality on three axes - platform coverage, test cases, and user conditions - the metrics from the Coverage Cube show how long it takes to run your regression testing suites. 

Once you have a better understanding of your testing capacity, your team can make decisions about when to do regression testing and how to speed up the regression testing process in a more efficient way.

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The Benefits of Regression Testing

Now that you know what regression testing means, let's discuss its benefits. Simply put, it's an essential piece of the testing lifecycle and DevOps process. 

  • Regression testing helps find major defects after an update and soon enough so that it can be fixed with minimal impact on customers. 
  • Regression testing creates a risk mitigation strategy so that companies can stay ahead of the curve with changes and fix problems before they really become issues. 
  • Regression testing modifies code for new features so that the software can still meet any requirements or business flows without causing problems. 
  • Regression testing can run 24/7 which frees up testers for exploratory testing.
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Regression Testing Example

Let us consider the following two regression testing example: one that reflects an internal change within the organization and one that reflects an external change that impacts your application under test. 

For the first example, let us say you are a mobile banking application, and you want to improve your user experience by showing each user’s balance in a larger font in a different color that is higher up on the home screen. To ensure that any of these code changes do not negatively affect any other area of the application, regression testing is required.

For the second example, now imagine that most of your user base uses Android phones. When the next Android version is released, you need to run your regression testing suite to ensure that the application still works properly on the latest operating system.

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Regression Testing Techniques

There are a variety of ways to go about regression testing. Especially for more established or mature applications, it is neither necessary nor cost and time-effective to run regression tests for every project element from the beginning. 

Some more popular regression testing techniques include:

  • Complete regression testing.

  • Partial regression testing.

  • Test case prioritization.

  • Progressive regression testing.

Let us take a closer look at each one. 

Complete Regression Testing

This regression testing techniques is as comprehensive as it sounds, but it should not happen all the time. While running regression tests for all of your existing suites may seem like a good idea as a best practice, it is often not the best allocation of time or resources, plus it can be very costly.

Team should only consider complete regression testing when an update happens that truly affects the entire application. 

Partial Regression Testing

Partial regression testing involved dividing the application into smaller, coherent units to maximize testing efficiency. These smaller units typically are the most critical to the application functioning properly.

Test Case Prioritization

This technique prioritizes test cases that will always be included in a regression testing suite. The focus when building these regression suites should be on robust test scenarios, high coverage, and near-zero test maintenance.

Progressive Regression Testing 

Progressive regression testing happens when the test scripts themselves are changed to align with new product requirements. This technique is used not only for code changes but when there is a larger change within the product vision itself.

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How to Manage Regression Testing

When it comes to managing regression testing with automation, there are a few must-ask questions and key considerations to keep in mind.

Related Reading: Automated Regression Testing: A Comprehensive Guide >>

Test Case Certification

Which test cases are certified and which aren’t? This will help you determine which to include in your regression suite. Check out this free on-demand webinar that will guide you to know exactly which tests to automate.  

Execution Schedule

What does your execution schedule for the regression suite look like? Think about whether it will be beneficial to do this weekly, daily, or by some other schedule. 

Execution From the Main CI Engine

Will all regression tests in the regression suite be executed from the main CI engine? Or are there others executed from a different scheduler? 

Maintenance and Improvements

What triggers regression suite maintenance and improvements? Are there certain events that inspire maintenance? 

Analysis

Are you continuously analyzing the value of your tests? Find out which are flaky, which aren’t producing the value you need, etc. Adapt to what you determine your testing needs. 

Continuous Testing

One round isn’t enough. Performing continuous testing is how you’ll get the most out of your regression tests, and it should be a process incorporated into overall DevOps.  

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Best Practices for Regression Testing

Here are our top best practices for leveraging automated regression testing in Agile.

1. Understand Scope

Testing can vary in scope, time windows, platform coverage, and objectives. It’s important to understand the differences in these scopes if you’re running sprint-level regression tests or full regression test cycles. 

2. Clarify Requirements

To build a successful regression testing suite, it is essential to clarify what’s important for you, as well as the product team, your customers, and other stakeholders.

Questions you should ask yourself include:

  • Frequency of running the regression testing suite. 
  • How to define major changes.
  • Deadlines for reaching full regression coverage.

3. Stay Up-to-Date on Regression Suites

Like all types of testing, you need to stay up to date with your regression suites. Keep in mind both the high-value functional and the non-functional scenarios. Always maintain the high-priority, high-value test cases in your suite. Ensure that your entire team is aligned to which test cases are top priority.   

4. Automate the Right Tests

If a test is difficult to automate or scale, you’re risking the whole cycle and are better off leaving it out. If a test is not able to be automated, strongly consider leaving it out of the regression suite. 

5. Stay on Top of Change

Change is a constant, especially in web and mobile software development. This means you must have a process to stay aware of necessary modifications, from changes in features or new Agile requirements. 

Related Reading: Keeping Up With Mobile Testing Trends for a Winning Test Coverage >>

Another area of web and mobile software development that is constantly changing is the application capabilities themselves. Teams must be prepared to incorporate testing of these more advanced features into their regression testing suites, such as:

  • Biometric authentication.
  • Simulation of network conditions (loss of connectivity, bad network coverage).
  • Simulation of location.
  • Image injection, such as barcodes or QR code scanning.
  • Voice or audio injection.
  • SIM cards.
  • Full control of system settings (i.e. Offline mode, Low battery mode).

Communication among developers and testers is essential so that changes do not fall through the cracks.  

6. Organize Processes

There are various tools out there to help you organize and scale your regression testing processes, such as CI/CD tools. But it is important to organize your tests first before getting involved with CI/CD; Scaling too quickly might lead to wasting valuable resources.

7. Track ROI

ROI is important. Teams should always keep track of the ROI of executions. Make sure that reports from your regression testing tools are transparent, and that you can see the real results of test executions over time. 

8. Grade Test Scenarios

Compare and track what the differences are when processes and tests are run on different platforms. We also recommend assigning grades to test scenarios, so that you’re ensuring you’re properly prioritizing. 

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Bottom Line

When it comes to regression testing, Perfecto is your go-to partner. Know why tests failed and fix them quickly with Perfecto’s comprehensive test reporting and analytics. See all your test results in one unified place — including a CI dashboard, heatmaps, and individual test reports. Rich artifacts like screenshots, videos, HAR files, and vitals help you understand what went wrong. And ML-powered noise filtering keeps you focused on real defects, not noise.

Perfecto can help you leverage automated regression testing — and test more, faster. Try Perfecto’s all-in-one cloud testing platform. See how easy it is to create, execute, and analyze tests. Explore for 240 free minutes, test real user conditions, and get detailed analytics. 

See Perfecto in action and start regression testing today by signing up for a free 14-day trial.

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