What is Regression Testing?

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If you’ve ever seen a software engineer staring at a bunch of running tests like the future of their life depended on it, you’ve probably already seen the tail end of regression testing in software QA.

While their life might not be on the line, their ability to release a code update and shut down for the day could be. Indeed, few things are as gratifying as seeing a regression test suite turn green (pass with no issues), and seeing unexpected failures in regression tests can strike dread into the hearts of unsuspecting devs who were hoping to move on to other tasks.

So what exactly is regression testing, and why is it so powerful that it can ultimately make or ruin someone’s day? Below is a quick explanation, along with some advice about how your team can most effectively and efficiently maximize the value of regression testing in your software project.

The Basics of Regression Testing

Regression testing is a vital part of the software development lifecycle. It’s designed to ensure that all features within a software project are functioning as intended, even after modifications have been made. The term ‘regression’ refers to the act of going back to reconfirm that the previously working functionalities still work after changes.

The process begins when developers introduce changes to the codebase. These changes could be new features, updates, modifications to existing functionalities, or even configuration changes in the software environment. After the modifications, regression testing is performed to confirm that the software’s existing functionalities still work as intended.

The value of regression testing cannot be overstated. Without it, a minor change in one part of the software could have unintended consequences elsewhere, causing functionality breakdowns, poor performance, or worse. Such issues, if left unresolved, can result in a poor user experience, a potential loss of user trust, and damage to the company’s reputation. Thus, regression testing is essential for maintaining software quality and reliability in the face of constant changes and improvements.

Types of Regression Testing

1. Unit regression testing: This is the most granular level of regression testing, focused on individual components or units of the software. Each unit is tested in isolation to ensure that it still functions correctly after changes. This type of testing is typically automated and carried out by the developers who made the changes.
2. Partial Regression Testing: This type of regression testing is more targeted, focusing on certain areas of the software that are considered at risk due to recent changes. Partial regression testing can be less time-consuming than complete regression testing, but it requires a good understanding of the software and the potential impact of the changes to decide which areas need to be re-tested.
3. Complete Regression Testing: This is the most comprehensive form of regression testing, where all aspects of the software are retested. Complete regression testing can be quite time-consuming and is typically performed when the changes are significant and impact the software’s broader aspects. Typically, it has to be done prior to every release.

Each type of regression testing serves its purpose and is used depending on the scope and impact of the changes made to the software.

Creating a Regression Test Plan

Creating a well-defined regression test plan is crucial for the effective execution of regression tests. The plan guides the testing process, ensuring that it’s systematic, repeatable, and covers all necessary areas.

Firstly, the features that need to be tested must be identified. These are usually features that are directly or indirectly impacted by the changes in the code.

Once these features are identified, test cases must be written for them. A test case is a set of conditions under which a tester will determine whether one of the application’s features is working as it’s supposed to. Each test case should be precise, covering a specific scenario, and should clearly outline the expected outcome.

Prioritizing the test cases is another key aspect of the test plan. Factors to consider when prioritizing include the complexity of the feature, the risk associated with a potential failure, the impact on the user, and the likelihood of a change causing an issue.

The process of creating a regression test plan also involves regularly re-evaluating and updating the test cases. As the software evolves, so too should the testing process, to ensure that it continues to meet the software’s needs. This makes the test plan a living document, changing and growing alongside the software it supports.

The Role of Regression Testing in Agile Development

Agile development methodologies, with their emphasis on iterative development, incremental changes, and frequent releases, put regression testing at the center of the software quality assurance process.

The heart of Agile is continuous integration and delivery (CI/CD), where developers are constantly integrating new code changes, leading to frequent deployments. With each deployment, there’s potential for new issues to emerge or old ones to resurface, threatening the stability of the existing functionalities.

This is where regression testing comes in. As a crucial component of the Agile development process, regression testing is performed regularly to ensure these constant updates and changes do not disrupt the software’s existing functionality.

By catching and rectifying issues early in the development process, regression testing helps maintain the software’s integrity and quality. It ensures that the software is always in a state ready for deployment, or as it is often referred to in Agile terms, a ‘potentially shippable state’.

Regression testing in an Agile context also encourages close collaboration between developers and testers. Frequent testing and immediate feedback enable developers to address and rectify issues promptly, improving the software quality and speeding up the delivery time.

Moreover, the automated nature of most regression testing fits well within Agile teams’ fast-paced environments, where manual testing might be too time-consuming. Automated regression tests can be run as part of the CI/CD pipeline, providing quick feedback on the impact of recent changes, enabling rapid action if any problems are found.

Challenges in Regression Testing

While regression testing is crucial for maintaining and improving software quality, it does come with its challenges.

Scope management: As a software project grows and evolves, new features are added, and the existing ones are updated or removed. This growth impacts the scope of regression testing. The more features a software has, the more complex and time-consuming the regression testing can become.

Maintenance of test cases: Test cases need regular updates to remain effective and relevant as the software changes. This upkeep can be a significant task, especially for large projects with many test cases.

Test coverage: Ensuring comprehensive test coverage is another challenge. The goal is to test all the functionalities of the software, but given the constraints of time and resources, it’s often not feasible. Testers need to make strategic decisions about what to test and when, often focusing on high-risk areas or parts of the software most likely to be affected by changes.

False positives and negatives: These are test results that incorrectly indicate a problem (false positive) or fail to catch an issue that is present (false negative). Both can waste time and resources, either leading to unnecessary investigation or letting bugs slip through undetected.

Resource management: Regression testing requires a careful balance of depth and breadth of testing with available resources – time, manpower, and infrastructure. Testing everything thoroughly every time is often not feasible, so teams have to decide where to focus their efforts for the maximum benefit.

Despite these challenges, the benefits of regression testing – more reliable software, higher user satisfaction, and lower maintenance costs – make it an indispensable part of the software development process. Techniques such as test automation, risk-based testing, and test case prioritization can help manage these challenges and maximize the value of regression testing.

Benefits of Regression Testing

Despite these challenges, the benefits of regression testing are considerable. It increases software stability, ensuring that changes don’t inadvertently disrupt existing features. It improves user experience by preventing bugs and issues from making it into the live software. Additionally, it enhances developer productivity. Instead of fielding complaints and troubleshooting issues after a release, developers can catch potential problems during the development process, saving time and reducing frustration.

Since regression testing is often a gatekeeper for determining if a change should be deployed into production or not, regression testing is typically performed upon every software build and before release for teams using a modern software development lifecycle.

Why is regression testing automation so important?

You may already be starting to get a feeling that automating regression testing is of critical importance for modern software development teams.

For any team emphasizing a CI/CD process, the more frequently the team releases updates into production, the more regular regression tests will need to run.

Regardless of the frequency of software updates, as a software project grows and adds more features, the regression test coverage will likewise need to become larger in scope to account for testing more and more functionality.

Therefore, regression testing usually becomes such a broad and frequently performed function that teams quickly begin to realize that manually performing regression testing would create an unsustainable cost and bottleneck in the flow of updates into production. At the same time, regression testing is so critically important that it cannot be taken out of the software testing process without adding an extreme level of risk.

This is where automation of functional regression testing with a leading platform such as testRigor is a must-have for any software development team. testRigor allows teams to quickly and easily write regression tests using plain English, and automatically run the regression test suite upon each deployment with no manual intervention.

As one of the most advanced AI-powered test automation platforms on the market, testRigor can also help automatically prevent tests from becoming invalid due to superficial changes in the software project, like UI modifications, further reducing the need to perform manual maintenance across all regression tests.

In other words, testRigor is the best option for any team trying to automate as much of the regression testing process as possible. While it might not change the habit of anxiously staring at regression tests as they run, testRigor can at least keep everyone on your team happy – knowing that they don’t need to pour a lot of time and effort into creating, running, and maintaining your regression testing process.