What is Regression Testing?

What is Regression Testing

What is Regression Testing?

Regression Testing is defined as a type of software testing to confirm that a recent program or code change has not adversely affected existing features. We can also say it is nothing but a full or partial selection of already executed test cases that are re-executed to ensure existing functionalities work fine.

This type of testing is done to ensure that new code changes do not have any side effects on the existing functionalities. It ensures that the old code still works once the latest code changes are done.

Why Regression Testing?

Regression testing process is essential in the testing scope. As it can identify if code changes or enhancements are introducing new defects or disrupting existing functional tests.

Without a regression testing process, even minor code changes may have a chance of leading to costly errors. It is, therefore, a systematic practice to help maintain software quality. This method helps prevent the recurrence of known issues and boosts confidence in the software.

When can we perform Regression Testing?

Here are the scenarios when you can apply the regression testing process.

New functionality is added to the application: This happens when new features or modules are created in an app or a website. The regression is performed to see if the existing features are working as usual with the introduction of the new feature.

In case of change requirement: When any significant change occurs in the system, regression testing is used. This test is done to check if these shifts have affected features that were there.

After a defect is fixed: The developers perform regression testing after fixing a bug in any functionality. This is done to determine if the changes made while fixing the bug have affected other related existing features.

Once the performance issue is fixed: After fixing any performance issues, the regression testing process is triggered to see if it has affected other existing functional tests.

While integrating with a new external system: End-to-end regression testing process is required whenever the product integrates with a new external system.

How to do Regression Testing in Software Testing

As we discussed before, regression testing is triggered based on any change done to the software. It can be a bug fix, new feature integration, and so on. Whenever such work happens, the QA team performs the following activities given below. These tasks are performed before they kick off the regression test execution cycle.

  • Discuss with the development team about the specific modules and libraries that were touched on during the change
  • Discuss with the product owner about the change to the new feature and learn how it flows across or impacts other functionality.
  • Identify the tests from the existing test suite that the testers need to execute to regress the existing features.

Various regression testing techniques can be carried out for effective software quality assurance:

Regression Testing in Software Testing

Retest All

This is one of the methods for Regression Testing, specifically employing a regression testing suite. In this case, all the tests in the existing test bucket or suite should be re-executed. This is an expensive method as it requires a lot of time and resources.

Regression Test Selection

Regression Test Selection is a technique where some selected test cases from a test suite are executed. It helps test whether the modified code affects the software application or not. Here, test cases are categorized into two parts. The reusable test cases can be used in further regression cycles, while obsolete test cases cannot be used in succeeding cycles.

Prioritization of Test Cases

Prioritization of the test cases depends on the business impact, criticality, and frequently used functional tests. Also, prioritization of test cases based on priority greatly reduces the effort of executing regression tests.

Selecting test cases for regression testing

It was found from industry data that a good number of the defects reported by customers were due to last-minute bug fixes. This resulted in side effects, hence, selecting the Test Cases for regression testing is not an easy task.

An effective regression test suite can be built by selecting the following types of test cases –

  • Test cases from functionalities/modules that have frequent defects.
  • Functionalities that are more visible to the users
  • Test cases which verify core features of the product
  • Test cases of functionalities that have undergone more recent changes.
  • All Integration restrases
  • All complex test cases
  • Boundary value test cases
  • Selected happy path and negative test cases

Regression Testing Tools

If your software undergoes frequent changes, regression testing costs will escalate. As manual execution of test cases increases test execution time as well as costs. Automation of regression test cases is the smart choice in such cases. The extent of automation depends on the number of test cases that remain reusable for successive regression cycles.

The following are the most important tools used for both functional and regression test automation in software engineering:

1) testRigor

testRigor helps you to directly express tests as executable specifications in plain English. Users of all technical abilities can build end-to-end tests of any complexity covering mobile, web, and API steps. Test steps are expressed on the end-user level instead of relying on details of implementation like XPaths or CSS Selectors.



  • Free forever public version
  • Test cases are in English
  • Unlimited users & Unlimited tests
  • The easiest way to learn automation
  • Recorder for web steps
  • Integrations with CI/CD and Test case management
  • Email & SMS testing
  • Web + Mobile + API steps in one test

Visit testRigor >>

2) Avo Assure

Avo Assure is a technology-agnostic, no-code test automation solution that helps you test end-to-end business processes with a few clicks of the buttons. This makes regression testing more straightforward and faster.

Avo Assure


  • Autogenerates test cases with a 100% no-code approach
  • Tests across the web, desktop, mobile, and ERP applications. You can also test across Mainframes, associated emulators, and more with a single solution.
  • Enables accessibility testing
  • Executes test cases in a single VM independently or in parallel with smart scheduling
  • Defines test plans and design test cases through the mindmaps feature
  • Integrates with Jira, Jenkins, ALM, QTest, Salesforce, Sauce Labs, TFS, etc.

Visit Avo Assure >>

3) Subject7

Subject7 is a cloud-based, “true codeless” test automation solution. It unifies all testing in a single platform and empowers anyone to become an automation expert. This easy-to-use software enables fast, easy, and sophisticated authoring of regression tests. It doesn’t need a single line of code and offers high-scale execution that runs thousands of nightly tests.



  • Integrates easily with DevOps/Agile tooling using native plugins, in-app integrations, and open APIs.
  • High-scale parallel execution in the cloud or on-prem with enterprise-grade security.
  • Flexible reporting of defects, with video capture of results.
  • Simple, non-metered pricing, delivering financial predictability.
  • SOC2 Type2 compliant

Visit Subject7 >>

Selenium: Selenium is the most used open-source tool used for automating web applications. Selenium can be used for browser-based regression testing. It supports programming languages such as Java, Ruby, Python, etc.

Quick Test Professional (QTP): HP Quick Test Professional is automated software designed to automate functional and regression test cases. It uses VB Script language for automation. It is a Data-driven, keyword-based tool.

Rational Functional Tester (RFT): IBM’s rational functional tester is a Java tool used to automate the test cases of software applications. This is primarily used for automating regression test cases, and it also integrates with Rational Test Manager.

Types of Regression Testing

Types of Regression Testing

Here are the different kinds of regression testing:

1) Unit Regression Testing (URT)

This is a very focused approach where only the modified section goes under the regression test instead of the impact region. In this way, the other portions of the module remain unaffected.


As an example, in Build 1, an issue was found and reported to the developer.

Let’s say it was a bug in the login functionality. So the developer fixes it, adds the bug fix in Build 2, and submits it. The testing team checks only if the login feature is working as expected instead of checking other features.

2) Regional Regression Testing (RRT)

In regional regression testing, the modification and impact areas are tested. This area is examined to find out if any dependable modules might be affected by the changes.

Example: In this example, in the first build, the modules A, B, C, and D are sent for testing by the developer. The tester finds bugs in module B, so the application is returned to the developer to fix the bugs.

Once the developer fixes the bugs in the second build in module B, it is sent to the test engineer again. The test engineer learns that fixing module B has affected A and C.

Hence, the tester checks module B’s modifications in the second release. Then, tests the impact regions in A and C as well to identify how they have been affected.

Note: While regression testing, there is a possible issue that this problem below may occur.


  • In build 1, the clients usually ask for changes, modifications, and added features.
  • This request is then sent to both the development and testing teams.
  • The development team then makes the modifications. Next, the test engineer emails the client, informing them of the areas the modification will impact.
  • The test lead then gathers the affected areas’ list from the client, the developers, and the testing department.
  • The impact list is then sent to the test engineers, who start regression testing.

This type of testing method creates communication gaps. The developers and the customers cannot always revert to the emails; hence, there is no proper overview of the impact area.

Solution: To remove this kind of problem, the testing team can arrange a meeting once the new build arrives after bug fixes, new features, and modifications. This meeting will be held to discuss whether the modules are affected due to the modifications.

There will be a test round to find impacts so they can create an impact list. The test lead adds the maximum number of areas in the impact region in this list.

Here, below is how the process will look like:

  • “Build verification test” to check the main capabilities of the application.
  • Testing of all new features.
  • Examining changed or modified features.
  • Retesting of bugs.
  • Then, finally, impact area analysis using Regional Regression testing.

3) Full Regression Testing (FRT):

This testing covers all the functionalities of an application. Full regression testing is usually performed in later releases. Thus, you can use FRT after the first few releases and as the final test before launching.

In the second or third build, the customer or the business owner may ask for modifications. They may also demand new functionalities and or report defects. The testing team then conducts impact analysis, makes all the modifications, and performs a final complete product test.

For example, the 4th build is the final release before the launch. So, in this build, the testing team performs a complete test or retest of the product instead of just the impact area or a feature. This is done after the modifications and tests in builds 1, 2, and 3.

To perform complete regression testing, you have to consider these circumstances:

  • Changes are performed on the core components of the application. For example, if there is a modification in a root file of an app or core modules, then the whole application needs to be regressed. If are numerous changes made.

4) Corrective Regression Testing:

This testing is done when no modifications are made to the features. Such tests can be performed with existing cases.

5) Retest All Regression Testing:

In this form of testing, all the minor to major changes made in the application from the origin or build 1 is retested.

This testing is done when all other regression tests fail to identify the root cause of the issues.

6) Selective Regression Testing:

This is conducted to check how the code reacts when a fresh code is added to the program. In order to conduct this test, a sub-set from existing cases is used to make it efficient and cost-effective. Criteria for selecting a subset are based on the modified code modules, dependencies, criticality of the affected functionality, and historical defect data.

7) Progressive regression testing:

This type of regression testing produces important outputs when specific changes are made in the program and new test cases are created.

It helps ensure that no components from the older versions have been affected in the latest version.

8) Partial Regression Testing:

Partial Regression Testing is used to verify that new code changes or enhancements do not impact existing functionality negatively. However, unlike a full regression test, which involves retesting the entire application, in partial regression testing, we focus only on specific parts of the software affected by the recent changes.

Therefore, the primary purpose of partial regression testing is to save time and resources by avoiding the retesting of unchanged parts of the application. Test cases for partial regression testing are carefully selected based on the impact analysis of the code changes. Identifying the correct test cases to include in the partial regression test suite is crucial. Missing critical test cases can lead to overlooked issues.

Automated Regression Testing

As mentioned earlier, automating regression tests is necessary when there are multiple releases. It is also required for multiple regression cycles and numerous repetitive activities. Since performing multiple test cycles across releases is very time-consuming.

However, with automation, you can test several times. This requires writing automation test scripts for execution, which needs relevant planning and designing. In such testing, the team cannot directly start with automation. Therefore, we need to involve both manual testing and automation testing teams to cover this scope. Here is how automated regression testing is done:

Step 1) The manual testing team checks all requirements and identifies the impact region. After this process, they forward the requirement test bundle to the automation team or automation engineer.

Step 2) The manual testing team begins testing the new modules while the automation test team writes the script and automates the test case.

Step 3) Before using this method of a regression test, the automation team identifies which cases will support automation.

Step 4) They convert those regression tests into scripts depending on which cases can be automated.

Step 5) During the scripting process, the automation team refers to the regression test cases. They do so as they may not possess the product nor the tool and app knowledge.

Step 6) When the test scripts are completed, the automation team will execute them on the new app.

Step 7) After the execution, the result informs if the test was a Pass or Fail.

Step 8) If the test fails, it is re-checked using the manual testing method, and if the issue exists, it is reported to the respective developer.

Note: After the bug is fixed, the issue and the impact area are sent to the manual tester for retesting, and the automation team re-executes the script.

Step 9) This process continues until all the newly added regression features get a Pass status.

Here are the benefits of automated regression testing:

  • Reusable: Its test scripts are reusable across multiple releases.
  • Accuracy: The automation tools perform the task redundantly, reducing the chance of error.
  • Saves time: It is faster than the manual functional testing process and is time efficient.
  • Batch execution: It is possible to execute all the scripts simultaneously and parallelly in automated testing.
  • No resource increase required: The regression test is bound to increase with every new release. However, you do not need to add new resources for automation.

How to choose test cases for the regression testing?

Here is how you can select the right case for regression testing.

  • Understand the scope of the changes and determine the parts of the application that have been modified, added, or fixed. You can then focus on these areas for regression testing.
  • Have a suite that covers the critical functionality and maintains this as the baseline for regression testing. As discussed earlier, it is highly recommended to have these tests automated.
  • Prioritize tests based on the criticality of the functionality, impact on the end user, and historical defect data.

Regression Testing Best Practices

Below are a few key practices that you should follow when maintaining regression tests.

Automate Wherever Possible

Automated regression testing reduces the testing effort and allows for quick execution of a large number of test cases.

Continuous Integration

Incorporating regression testing into the CI/CD pipelines ensures that tests are automatically run whenever changes are committed to the codebase.

Test Case Selection

Identify and maintain a subset of test cases that represent core functionality and high-risk areas. You can also choose those directly related to the changes being made because running all previous test cases may be impractical.

Regular Execution

Execute regression tests regularly, especially after every code change. This helps in identifying issues early in the development process.

Test Data Management

Ensure that test data used for regression tests are consistent and manageable because data-related issues can affect test results.

Environment Management

Maintain consistent and reproducible test environments. This includes using the same operating systems, browsers, and device configurations used in production.

Record and Track Defects

Any defects discovered during regression testing should be logged, tracked, and managed. Prioritize their resolution based on severity.


Create reusable test scripts and test data to reduce duplication and improve maintainability.

Regression Testing and Configuration Management

Configuration Management during regression testing becomes imperative in agile Environments where a code is being continuously modified. To ensure effective regression tests, observe the following:

  • Code being regression tested should be under a configuration management tool.
  • No changes must be allowed to code during the regression test phase. Regression test code must be kept immune to developer changes.
  • The database used for regression testing must be isolated. No database changes must be allowed

Difference between Retesting and Regression Testing

Retesting means functional testing of the defect or bug again to ensure the code is fixed. If it is not fixed, the defect needs to be re-opened. If fixed, the defect is closed.

Regression testing means testing your software application when it undergoes a code change. It is done to ensure that the new code has not affected other parts of the software.

Here below are the primary differences between these two tests:

Retesting Vs Regression Testing

Retesting Regression testing
It is built specifically for defect fixes. Regression testing is done mainly to verify if code changes have impacted other functionalities.
Retesting doesn’t check the other versions and only verifies if the broken functionalities are restored. Focuses on previous versions, and it tests if the previous functions are still working as expected.
Each test is specific Regression is a generic test.
This testing is for failed test cases. It is for passed-test cases.
It checks specific defects, so it cannot be automated. Can be automated. Also highly recommended to be automated as we discussed earlier.
Retesting is not always a part of a testing cycle, as it is required only when bugs are found. Regression is always a part of testing, as every time a code is changed, this test must be conducted to understand if the product functionality is stable.
It is high-priority testing as it focuses on known issues. This is low-priority testing, as it is overall testing of possible defects.
This testing is not time-consuming as it works on a specific defect. As it involves a large area of the software, hence, it is time-consuming.
It determines defects with the same data and environment with a different input and a new version. This testing can acquire cases from user manuals, defect reports, and functional specifications.
Retesting cannot be conducted without the first testing. It is done when changes and modifications are obligatory in the existing project.

Also, Check out the complete list of differences over here.

Advantages and Disadvantages of Regression Testing


  • Regression testing improves the quality of the products.
  • With this testing, you ensure that the modifications and bug fixes have not changed the existing functionalities and features.
  • Since regression beds are run on existing features, we can guarantee older defects are covered too.
  • It facilitates efficient product development.
  • You can achieve high user satisfaction with this testing in place.
  • Overall, it maintains the stability of the software.


  • It should be conducted every time a small change is made, as the slightest change can bring issues in existing modules.
  • This test can be time-consuming when conducted manually, requiring repeated testing.

Challenges in Regression Testing

Challenges in Regression Testing

Following are the major testing problems for doing regression testing:

  • With successive regression runs, test suites become fairly large. Due to time and budget constraints, the entire regression test suite cannot be executed
  • Minimizing the test suite while achieving maximum remains a challenge
  • Determination of the frequency of regression tests, i.e., after every modification or every build update or after a bunch of bug fixes, is a challenge.

Practical Application of Regression Testing Example with a Video

Click here if the video is not accessible

Regression Testing Example – Amazon

Consider the e-commerce giant Amazon, which is a multi-billion-dollar business that relies on its website for revenue generation. To uphold its functionality, reliability, and performance, regression testing plays a crucial role.

Let’s take a scenario of Adding a New Product Category.

Imagine that Amazon decides to expand its product offerings by introducing a new category called “Smart Home Devices” alongside existing categories like “Electronics” and “Clothing.”

Possible regression cases would be:

Homepage Functionality: Verify that the homepage displays the new “Smart Home Devices” category alongside existing ones without any display issues.

Category Navigation: Ensure that users can smoothly navigate to the “Smart Home Devices” category page and return to the homepage without glitches.

Search Functionality: Ensure that the search bar accurately returns results for smart home devices when users search for them and do not mix with other products.

User Accounts: Verify that user accounts can be created, updated, and utilized for purchasing smart home devices and other products.

Payment Processing: Test payment gateways specific to purchases and guarantee secure and error-free transactions.

Mobile Responsiveness: Check that the website remains mobile-responsive, allowing users to access and shop for smart home devices on various devices.

If any of these regression test cases fail, it indicates an issue with the website’s existing functionality due to the addition of the new product category. This problem should be documented and resolved immediately. Additionally, as Amazon continues to expand its offerings and make changes to its website, these regression tests should be executed to maintain a reliable online shopping experience. Automated testing tools can streamline this process.


  • Regression Testing meaning – Regression testing is a type of software testing that ensures an application still functions as expected after improvements, any code changes, or bug fixes.
  • An effective regression strategy can save both time and money for the organization.
  • As per case studies, regression saved up to 60% of the later bug fixes.