What is Regression testing? A complete introduction for beginners


Regression testing

Regression testing is a testing practice that is widely used in software teams nowadays due to its superior benefits. This practice ensures stable performance and functionality as well as accelerates the time-to-market of software products. This article provides a complete introduction of Regression testing for beginners by walking through its notions, benefits, process, and techniques to implement. 

What is Regression testing? 

Regression testing is defined as a testing practice applied to guarantee the application still behaves as expected whenever any code changes, updates, or improvements occur. It is typically the final step in a testing process before changes are integrated into the main development branch. Thus, regression testing is responsible for the overall stability of product functionality. 

In a complex system of software products, a mild alternative can lead to dependencies, defects, or malfunctions. Therefore, regression testing is a secret weapon to eliminate these risks and prevent adverse effects on the product’s key function.

In software development, product teams typically apply regression testing under these circumstances:

  • Add a new requirement to an existing feature
  • Add a new feature or functionality
  • The code base is fixed to solve defects
  • Optimize the source code to enhance performance
  • Add patch fixes
  • Changes in configuration

The benefits of Regression testing

  • Locate and fix bugs early in the deployment pipeline, so that minimize time, costs, and efforts to resolve build-up defects. 
  • Enable developers and testers to verify the compatibility between updated and existing codes. Thus, it’s less difficult to detect the root cause of any test case failure. 
  • Continuous deliver informative feedback among the product team, helping them respond to possible risks more quickly and effectively.
  • It is optimal for those products requiring numerous alternatives and continuously verify product performance as a whole.

Regression Testing benefits

The process of regression testing implementation

  • Detect changes in the source code; then identify the components that need to change or update as well as their effects on existing codes.
  • Streamline the testing process base on the priorities of those changes and product requirements.
  • Determine Entry point, Entry criteria to make sure the application fulfills the preset eligibility before testing.
  • Determine Exit point for eligibility set in step three.
  • Schedule the testing time to execute.

Regression testing techniques may vary among different organizations. However, three widely adopted prevalent methods include complete regression, partial testing, and test case prioritization.

  • Complete regression: Testers can use regression testing for all test suites. Although it may cost much time and resources to test all existing test suites, this method is the safest way to eliminate all potential risks in the future.
  • Regression test selection (partial regression): Pick out some areas relevant to new code changes and run regression testing on those parts only. Thus, this technique requires less time and effort by limiting the number of test suites.
  • Test case prioritization: Take into account some criteria like failure rate, business impact, and product functionalities and choose some test case priorities to implement first.

Regression testing vs. Re-testing practice

Many people are regularly confused between two types of software testing due to their similar sounds. However, they are two totally separate testing terms.

Regression testing is responsible for eliminating all underlying side effects caused by code modifications in the most effective way.

Re-testing literally means that the test case is implemented again for a specific reason. For example, you run a test case and find out some defects that cause various adverse effects on your application functionality. After fixing these bugs, you have to re-run this test case to ensure product verification.

Testers applied regression testing to passed test cases to validate the product behavior as a whole after newly added codes. In contrast, re-testing on the failed test cases can verify errors.

Test automation tools recommendation for Regression testing

Automation test is key to regression testing as it eliminates the time-consuming of running manually. Various automation testing tools assist testers in executing this practice are Katalon Studio, Selenium, Watir, IBM Rational Functional Tester, Apache JMeter

Want to know more automation testing tools? Check out 5 Best Performance Testing Tools for 2020


Adopting regression testing practice enables your organization to optimize the budget, process time, and resources invested in software development. Therefore, a profound understanding is crucial in building appropriate test strategies, leading to more significant competitive advantages for your products.

Read more about Regression testing. 


Leave a Reply