What is Regression Testing & Why Should it Be Automated?

June 5, 2026

Regression testing is one of the most common types of testing in software development. It requires going back, or “regressing,” to existing code and ensuring it isn’t negatively affected whenever new functionality, features, or updates are added. Said another way, regression testing ensures that everything still functions as expected after a change is introduced to an application.

Regression testing is the only way to confirm whether updates or changes have introduced new defects into existing functionality, making it a critical checkpoint for maintaining application stability. In a normal software development pipeline, retesting comes before regression testing procedures. This type of testing is especially important in enterprise applications like Oracle and Workday, where vendor updates are frequent, and a single change can cascade across interconnected business workflows.

In this blog post, we’re covering the most asked questions about regression testing, including why it should be automated and how Opkey’s AI-powered cloud application lifecycle management (CALM) platform helps enterprises test faster, reduce manual effort, and protect application stability across every update cycle.

Regression testing is the practice of re-running existing test cases after code changes to ensure previously working functionality has not broken. Opkey automates regression testing for enterprise applications including Oracle, SAP, and Workday, reducing regression cycle time by up to 80% without writing code.

What Is Regression Testing in Software Development?

Regression testing is an essential type of Software testing. It is the process of evaluating already-released software to ensure that no functionality has been broken as a result of any change or modification. Overall stability and functionality of current features are ensured by corrective regression testing.

What Are the Different Types of Regression Testing?

There are seven different types of regression testing:

• Corrective testing: It is the simplest type of regression testing. It is used to test existing functionality when no changes have been made to the original source code.
• Re-test all: This type of Software testing technique reruns all test cases whenever changes are made to an application’s existing code, such as a major software update or a re-platform.
• Selective regression testing: This type of regression testing “selects” just certain parts of an application to test the impact of new code on existing code.
• Progressive regression testing: This regression testing is performed when new features are added to ensure existing code is not affected.
• Complete regression testing: This is comprehensive testing that is typically performed during the final deployment phase of a project just prior to release.
• Partial regression testing: It takes place when changes are made to the source code to verify that the application is still performing as expected.
• Unit regression testing: This type of testing isolates specific pieces of code to test so that any dependencies on that code are not affected.

How Does Regression Testing Differ from Other Types of Testing Like Unit or Integration Testing?

While regression testing, unit testing, and integration testing are all essential parts of a software testing strategy, they serve distinct purposes. Unit testing focuses on validating individual components or functions of code in isolation, typically written and run by developers to catch bugs at the smallest possible level. Integration testing, on the other hand, checks whether multiple components or systems work correctly when combined. Regression testing operates at a broader level: it re-validates the entire application, or significant portions of it, after a change has been introduced, ensuring that previously working functionality hasn’t been broken. Think of it this way: unit testing asks “does this piece work?”, integration testing asks “do these pieces work together?”, and regression testing asks “does everything still work the way it did before?” This makes regression testing uniquely critical in fast-moving development environments where frequent updates, patches, or new features are constantly being pushed; particularly in enterprise systems where a single change can ripple across dozens of interconnected workflows.

Is Regression Testing Part of UAT?

User Acceptance Testing (UAT) is the final stage of the software testing process. However, regression testing is not actually part of UAT testing. It should be performed before user acceptance testing to reduce the risk of poor user acceptance.

What is the Regression Test Suite?

The regression test suite is a set of already created test cases that confirm the functionality of the product. In the quality assurance process, this can span from unit tests, functional tests to integration tests.

What are the Regression Testing techniques?

Continuous software maintenance encompasses a wide range of activities such as modifications, error correction, optimization, etc.

• Re-test All: All tests in the current test bucket should be executed again. This is quite expensive because it takes a lot of time and resources.
• Regression test selection: Run the selected portion of test suites, such as reusable or obsolete test cases.
• Prioritization of test cases: Prioritization of test cases is based on business impact and used functionality.

When Should You Perform Regression Testing?

You can perform regression testing at any stage of the software development lifecycle. However, the regression testing process must be carried out in the following scenarios:

• When adding a new feature or functionality: Introducing new features or functionality can negatively affect the current application and pre-existing integrations and customizations.
• When changes are made to the existing application: Even small tweaks or modifications can wreak havoc on overall functionality. Changes such as adding a new field or minor workflow adjustments can trigger the need to run regression tests.
• When integrating with other applications: New integrations with third-party applications require code changes that can break or disrupt previous functionality.
• When there is a software update: Continuous regression testing is required for regular software updates, such as those released by enterprise suppliers, to ensure that previous functionality is not impacted by newer updates.
• When there are performance issues: Even if no system modifications have been made, executing regression tests is still a good idea. Whenever you’re experiencing performance issues, it can usually pinpoint the problem areas that are causing performance issues.

How Do You Improve Regression Testing?

Effective regression testing strategies involve proper planning and selecting the right regression testing tools. Creating the perfect regression test suite involves the following steps:

• Collecting all expected regression tests and monitoring changes carefully
• Prioritizing regression tests and calculating the time needed to run them
• Analyzing the changes and their impacts on various components
• Identifying the areas that are more vulnerable to risks and failures
• Updating the regression tests guarantees that the test suite is up to date with the most current changes introduced in the application.
• Encouraging teams to perform regression testing within defined intervals of time to ensure that the application continues functioning properly

What Is Enterprise Regression Testing?

Enterprise Resource Planning regression testing is simply doing regression testing on a packaged application such as Oracle, SAP, Salesforce, or Workday. In general, functional testing is performed during the initial enterprise implementation, but as your application grows, various regression testing techniques must be employed. Enterprises migrate to the cloud, along with critical enterprise integrations. You’ll have to cope with frequent updates and you’ll now need to perform regression tests to get the most out of your enterprise system.

However, regression testing is also recommended post-launch whenever new features or integrations with third-party applications are added.

What Are the Benefits of Automated Regression Testing?

Regression testing is typically performed by QA teams and, in some cases, business users. The sheer volume of application changes makes regular regression testing challenging, especially when enlisting the help of non-technical business users. You must automate regression testing to keep development schedules on-time and under-budget.

The benefits of automated regression testing have been thoroughly covered in our blog post, “ Why Automated Regression Testing is Key to Enterprise apps Success**.”

Of course, regression testing gets the most use whenever enterprise platform vendors roll out their latest update, which is happening on a much more frequent basis these days. Struggling to keep up with so many updates is one of the main reasons organizations decide to implement automated regression testing. With complex enterprise integrations and customizations, manual regression testing is simply overwhelming. Most businesses can’t afford to hire more testers to handle the increased workload. This is why automated regression testing makes sense.

Here are just some of the key benefits that test automation provides with regards to regression testing:

• Automated regression testing eliminates menial, repetitive tasks. The regression test suites expand each time you add new features. It becomes challenging to run the full regression suite within a short timeframe, such as the two-week timeline given by Oracle for its updates. Automation empowers teams to run their full suite of regression tests in a shorter amount of time, and frees users from monotonous, boring work.
• Automating regression tests helps you improve application stability & performance. As enterprise cloud applications become more complex with each update, manual regression testing techniques become more prone to human errors. Automation helps reduce the possibility of human error, resulting in a much more stable application.
• Automated regression testing is built for scale: Automated regression tests, once created, can be used over and over again in the future, eliminating the need to re-create them multiple times. Additionally, automated regression test cases can be run all day, at any time of day, unlike human, manual testers.
• The regression testing process, which is automated, provides greater coverage. Knowing what to test, when to test, and how often to test can be challenging when done manually. Intelligent test automation platforms leverage the power of AI to perform a deep dive into your business processes to help you identify which business processes need the most testing, helping you quickly achieve optimal coverage.

How Does Opkey CALM Platform Streamline Regression Testing?

Opkey’s end-to-end Cloud Application Lifecycle Management platform helps enterprises reduce the cost, effort, and time associated with regression testing, while protecting application stability across every update cycle. Here’s how:

• Argus AI-powered test automation reduces testing sprints from weeks to hours. Opkey’s proprietary Argus model, trained on 200+ terabytes of enterprise application data, intelligently recommends, executes, and repairs test cases with 91% inference accuracy.
• Self-healing test suites automatically detect and fix broken tests after application changes, reducing test maintenance efforts by up to 80% and keeping your regression suite aligned with every update.
• Change impact analysis gives a detailed view of how a release update will impact business flows, automatically flagging affected processes and prioritizing the right regression test cases, to replace guesswork from every release cycle to confident certification.
• End-to-end testing validates that all enterprise integrations, configurations, and customizations perform as expected after each application change, update, or release; across Oracle, Workday, Salesforce, Coupa, and more.
• No-code test creation allows non-technical users to build and manage automated regression tests intuitively, so testing doesn’t bottleneck on engineering teams.

FAQs

What are the best practices for automated regression testing?

The most effective best practices include prioritizing test cases based on business impact, maintaining a test suite that evolves with the application, and automating repetitive test runs within your CI/CD pipeline.

How do you decide when to run regression tests during a software release?

Regression tests should run whenever a code change, bug fix, new feature, or vendor patch is introduced, particularly in Enterprise apps like Oracle or Workday with frequent release calendars.

What is the relationship between regression testing and machine learning?

Machine learning is transforming how regression testing is planned and executed. By analyzing historical test data and code change patterns, ML models can predict which test cases are most likely to catch defects, enabling leaner, smarter test cycles.

What exactly is regression testing and when should I run it in a project?

Regression testing can be performed manually or by automating a set of specific test scripts. Certain issues demand the highest level of accuracy and productivity, which can only be achieved with automated testing.