How to do Regression Testing (Faster)

Maria Homann

Automation Expert

Regression testing is a pivotal component of both quality assurance and software testing. Yet, some QA teams rush through or skip this process due to its perceived time consumption. Fortunately, with the right approach, regression testing doesn't have to be a bottleneck.

In fact, when executed efficiently, regression testing can save considerable time for QA teams and testers, enhance product quality, and free up time for more engaging tasks.

What is regression testing?

The software development life cycle involves planning, developing, releasing, and maintaining software. Part of this process is testing new features and functionality before releasing updates to users. 

Every now and then, however, updates go wrong. Despite rigorous testing of new features, existing features might be affected unintentionally, causing disruptions to the user experience.

That's why regression testing is crucial.

Regression testing is the process of testing existing features when new functionality is introduced. Note that regression testing is not to be confused with retesting

In other words, regression testing is the re-running of functional and non-functional tests to ensure that no newly developed code causes bugs or breaks any existing functionality in the software.

The purpose is to detect any unwanted changes to ensure that the tested software still performs as desired after a change.

Access guide to moving from manual to automation testing

How to improve regression testing

There are many ways to approach regression testing. In this blog post, we focus on guiding you towards faster and more efficient regression testing.

Let’s start from the top.

1. Build your regression suite

To do regression testing, a tester must build a regression suite. A regression suite is essentially an overview of the different functionalities that your software consists of, and that you’ll therefore want to test. These are also called test scenarios.

Building a regression test suite doesn’t necessarily require a lot of work. The suite can be created from the existing test cases – functional tests, integration tests, unit tests, etc. – that you probably already have. Anything that has previously successfully verified that the software functions as intended can be used in your regression suite.

Over time, as your software system grows or changes, your suite will grow as well, numbering into perhaps hundreds or thousands of regression test cases. This is why automation will inevitably become part of your testing process at some point.

Related reading: 5 Reasons Why You Should Automate Regression Testing

2. Select a regression testing approach

How much of your testing should be automated? The answer to this question largely depends on your approach to testing; will you write all your test cases upfront and stick rigidly to these when testing, or will you take a more exploratory approach where your testing is more free and unstructured?

The approach you choose should ideally fall somewhere on a spectrum between the two.

structured vs exploratory testing approach

Automation is not just beneficial but essential to the agile software development team, as it enables them to perform regression tests more efficiently. But it does have its limitations – and it requires an understanding of these to be able to reap the benefits of automation.

The limitation (which could also be viewed as a benefit) is that automation robots will check exactly what you ask them to. Nothing more and nothing less.

As your software grows and changes, your testing requirements will inevitably grow and change as well, and the tests that you previously set up to test the product as it was at a given time may no longer be fit for what the product looks like at a later time.

This is where critical thinking becomes crucial to the testing process. It is up to the testing team to review and evaluate the results of the test.

The great thing about automation is that, when done right, it can free up testers' time and let them work on test design and improvement.

You can read much more about striking the perfect balance between automation and manual testing in our blog post: Test Automation and Manual Testing: 10 Considerations.

However, when setting up your automated regression tests, it’s still up to you to decide what goes into the regression test suite and what doesn’t.

So how do you select your test cases?

3. Select your test cases for the regression suite

The four steps to selecting test cases for regression testing

As a starting point, if you haven’t built your test suite before and you need help figuring out where to start, it can be useful to select your test cases based on the following prompts:

  • Is the function core to your product? Is it essential for other functionalities to work? Core functions should always be tested.
  • Is the feature new, and has it been tested against numerous other feature updates before? New code tends to be more vulnerable.
  • Is the code sensitive to the environment being configured? Dependency on environment settings tends to be more vulnerable.
  • Has the code been defective before? It may pay off to pay extra attention to code that has previously been faulty.

Once you’ve considered these elements, you can set up the regression suite and schedule your regression tests.

Remember that you can always adjust your testing suite. As your team develops and tests, you’ll be constantly learning and adapting, so it’s only natural that your test suite will too. It’s crucial, however, that the tool you use to set up your tests provides a good overview and is simple to edit.

Related reading: Regression Testing Tools: Selenium vs. Leapwork

4. Decide the frequency of your test runs

Once you’ve built your regression testing suite, you need to decide how often you want the regression tests to run.

Manual testing creates more bugs

Regression: When you fix one bug, but you introduce several new bugs.

The picture above paints a clear picture and should serve as a reminder: Every time you let a bug out the door, you’ll want to make sure you haven’t let a swarm of new bugs in.

Regression testing should be performed whenever a change is made to the code. If your software system is large enough, this is only possible to do with automation.

Still, you'll need to decide the frequency of automation runs based on your project needs. Read our blog post How Frequently Should You Run Your Regression Tests to learn how to hit the right regression testing frequency, and to learn about on-demand vs. scheduled automated tests.

Plan your journey to test automation

A reliance on manual testing is the silent killer of digital transformation, as the inefficient nature of manual testing creates bottlenecks in the development cycle. By embracing test automation, you can remove those bottlenecks and ensure high-quality deliveries at speed. 

From Slow to Agile: A Guide to Moving from Manual to Automated Testing provides you with a tried-and-tested path forward. By following our steps to automation feasibility analysis, proving test automation ROI, and implementing automation, you can get off on the right foot and accelerate your time to value with automation.

Get the Guide to Moving from Manual to Automated Testing