June 5, 2023

The software testing procedure performs technical and functional verification and validation on software products. If the application previously passed the tests, it’s critical to rerun them. In this manner, we can be sure that the new program does not introduce new bugs or reintroduce old ones. Regression testing is the term for this kind of testing. There are two approaches two run regression tests: manual and automation testing.

To better understand how regression testing functions, I’ll introduce you to key topics in this article.

What is Regression Testing? 

Let’s first examine the following two types of software testing to understand regression testing better:

  • Whitebox testing: It is used to validate various software applications and focuses on the internal workings of the product.
  • Blackbox testing: It concentrates on the software’s generated output while ignoring the system’s internal workings. Blackbox testing is known as functional testing since it focuses on the product’s features under examination.

The category of black box testing includes regression testing. This type of testing looks for regressions in software.

Selection of test cases for regression technique

Test cases are the main elements of a regression test plan contributing the most to making it successful. Therefore, selecting the most appropriate test cases is necessary to get the best results.

Four main changes require regression testing, namely

  • New integration
  • New functions
  • Revised functions
  • Bug fixes

Consequently, the cases that were chosen fit into one of the categories listed below:

●       Emphasize test cases for the features that experience the greatest errors

●       Pick test cases for the most important functionalities of the product

●       Prioritize test cases to be excluded from regression testing

●       Choose test cases for recent product changes

●       Choose which test cases to update when an outdated functionality is modified

●       Identify integration testing test cases

●       Choose every end-to-end test case

Do small changes require regression testing?

The answer to this question is a BIG YES. There are many reasons for regression tests:

  • You can only narrow down problems if you know what changes have affected certain software features in the past.
  • You can maximize the value of secondary features. Your software might be used solely for secondary functions. In addition to the primary functions, secondary functions are often just as important.
  • You can proactively fix issues. Regression testing allows you to proactively detect problems before fixing them later. This saves you time, money, and additional effort.

How Much Regression Is Required?

The extent of the recently introduced features will determine this.

The application area impacted by a fix or feature if its scope is too broad is also rather broad, so all application test cases should be included in the thorough testing. But when the tester receives advice from a developer regarding the scope, nature, and amount of change, this can be decided successfully.

These tests are repetitive; thus, test cases can be automated to make it simple to run just a certain collection of test cases on a new release.

Regression test cases must be carefully chosen to ensure that the most functionality is covered by the fewest possible test cases. These test cases need to be continually improved to accommodate newly introduced functionality.

When the application’s scope is exceedingly broad, and the system is constantly receiving updates or patches, it becomes very challenging. In these situations, running only a few tests is necessary to reduce testing time and expense. These carefully chosen test cases are based on the system improvements made and the areas where they can have the biggest impact.

What are the types of Regression Testing?

Regression testing is conducted throughout several testing phases. Regression testing comes in a variety of forms for this reason. The following are a few of them:

  • Unit testing: When changes are made to the code for a single unit, the tester in charge of the code reruns all previously successful unit tests. Unit testing is far more effective than other testing methods because automated versions are included in the code.
  • Selective testing: To reduce the expense and effort of retesting, selective testing uses a subset of the current test case. A test unit must be restarted if the software entities it covers have changed.
  • Progressive testing: When software/application improvements are made, this testing is efficient since new test cases and specifications are created.
  • Retest-All Testing: This kind of testing involves testing every aspect of a certain application and reusing every test case, even when there haven’t been any changes. The application has little use when any minor adjustments are made to it. It takes a lot of time.
  • Complete testing: This testing is necessary when the existing code has undergone several changes. Performing this testing is quite beneficial for finding unforeseen bugs. After this testing is complete, the user can access the final system.

It is very important to know which type of testing is tailored to meet your requirements.

Implementation of Regression testing

The procedure for implementing regression testing is similar to the one you apply for any other testing process. The developer carries out these steps as part of the testing process whenever the software undergoes a change, and a new release comes up,

  • First, unit-level regression tests are run together with any new tests they have developed to cover new or updated functionality and validate the code they have modified.
  • The modified code is then merged and integrated to produce a new build of the application that is being tested (AUT)
  • Smoke tests are then run to verify the stability of your software before regression testing.
  • Integration tests are run after the build has been deemed successful to confirm how the application’s parts communicate with one another and with back-end services like databases.
  • Depending on the size of the released code, either a partial or complete regression is scheduled.
  • After that, errors are reported to the development team.
  • If necessary, additional regression tests are run.

Regression Testing Techniques

Regression testing verifies that changed software hasn’t been altered unintentionally and is often carried out using any combination of the following methods:

  • Retest-All: The complete software suite is simply retested using this way. These tests are typically run via automated tools. Automation is not necessary all the time. Given that it involves more time and resources than the others, this strategy is more expensive.
  • Test Selection: Using this approach, the team can select a subset of tests close to fully validating the test suite rather than selecting all the test cases. One of its key benefits is taking less time and effort to complete. The majority of it is carried by developers, who often have a greater understanding of the complexities of test edge cases and unexpected behaviors.
  • Test Case Prioritization: This strategy is used to rank a small number of test cases in order of importance by prioritizing more prospective test cases. Test cases are picked that could have an impact on both the current and next software versions.

These three techniques are used, and at times, according to the testing requirements, these techniques are combined.


Tools for performing successful Regression testing

  • Selenium
  • Rainforest QA
  • Appium
  • Ranorex studio
  • Watir
  • Serenity
  • TestComplete

Advantages of Regression Testing

If done appropriately, regression testing functions most effectively. It has the following advantages over conventional techniques and raises the caliber of the product being tested.

  • If any negative consequences appeared after the module or application was rectified or improved, we could identify them.
  • Both manually performing it and automating it with readily available tools are options.
  • It enhances the quality of the final product.
  • Testing that is automated can greatly lessen testing that is done manually.
  • Make sure the bugs that were discovered before don’t reappear.

Challenges of Regression testing

  • It is costly
  • It is difficult to optimize or maintain
  • It is time-consuming

By using a cloud-based infrastructure that can scale as your testing requirements increase, test execution and orchestration systems like LambdaTest can assist you in overcoming the majority of issues. For your test automation requirements, LambdaTest provides a cloud-scalable infrastructure comprising more than 3000+ actual browsers, devices, and OS combinations.

With LambdaTest, you can take advantage of the online Selenium Grid for the simple execution of thousands of parallel tests that take less time and reduce the amount of time required for test execution. It also offers faster feedback on code modifications.


Regression testing is streamlined and made understandable in this article. We hope this information will help you develop a successful regression testing approach.

Regression will get more complex, making it difficult to perform manually. The best approach is to pick an automation framework that matches your test needs, develop your test suite, begin automating your test cases, and reduce the manual testing you do.

Given that it is practically applicable to the test requirements of contemporary development, it is one of the most important concepts in software testing.

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