Regression Testing-The Central Pillar of Software Testing & its Best Practices


What is Regression Testing?

Regression testing is a critical type of software testing that is intended to ensure that a small change in one part of the system does not affect the functionality of the system. Regression testing allows testers to identify bugs and issues in the build when changes to code are made and ensures that all features work even after the changes are done. It is a black box testing approach that ensures any frequent code changes do not impact the product’s existing functionality. 

Why is Regression Testing Important?

Most obviously, software updates come with risks that can have adverse effects on the existing functions. Regression testing helps organizations to eliminate risks associated with updating their apps, websites, etc. These risks can range from bugs that limit certain functions to those that create security vulnerabilities. Consequently, software bugs introduced by software updates can result in frustrated customers leading to a negative brand image and losing revenues. 

When Should Testers Use Regression Testing?

Testers should consider using regression testing on a new build when there is a significant change in the original functionality even with a single bug fix. Typically, it is performed after verification of changes or when a new feature is added and testing should be repeated with every new function. It is also considered as a retest of tests and it can be performed in the following situations:

  • When products are enhanced 
  • When new features are added and code is modified 
  • Small changes made into the software configuration 
  • When new patches are added
  • When products are integrated with other products 
  • Code changes are made for a performance upgrade

In order to ensure all functionalities remain unaffected by the new changes, it is important to perform regression testing in the above instances. QA experts use modern software testing tools to ensure software quality. In agile environments, regression testing plays an important role since continuous testing is the key to achieving a product’s stability. 

Regression Testing Best Practices

Define Effective Regression Test Strategy 

In an agile environment, it is critical to define an effective test strategy for regression testing. It should include the following:

  • Gather all requirements acceptance criteria 
  • Move to gather test cases
  • Identify how the test cases can be improved
  • Estimate the time required for test case execution 
  • Defining which tests can be automated and those that need to be tested manually

These factors can help testers remain on track when performing regression testing. 

Test Automation 

In order to ensure developments do not break any existing functions, it is important to include regression tests in each release cycle – it is equally important to utilize test automation to save time and effort for the testers. If automated regression tests are performed parallel, then it can save time and subsequently improve product quality. Automated regression tests make the process more efficient as running the same tests by a manual tester can be tedious. Automation frees up resources and automated tests can reduce manual efforts on tedious and repetitive tasks. 

Smoke & Sanity Testing 

Before performing regression testing, testers should perform smoke and sanity tests, that can save their time. Sanity tests focus on ensuring a run-through of the basic app functionality. Whereas smoke tests are used to test the initial workflows such as login and startup pages, etc.

Update Regression Packs Regularly

A regression pack is a collection of test cases that are executed for new software updated for every new feature. It consists of test cases that have been written and drafted using the requirement specifications document. Testers should update these test cases with changes in features and it is also important to maintain these test cases to achieve effective test results. 

Continuous Testing 

Continuous testing is the backbone of software testing in an agile environment. The process focuses on testing fast and often so that defects are fixed fast by the developers. These defects are fixed before software delivery without affecting the software application. In addition, continuous integration (CI) and continuous delivery (CD) in agile practices require continuous testing with automated regression testing. 

Complete Regression Testing

Testers should perform comprehensive regression testing in order to address all the critical aspects of an application. It should be taken up to certify that the functionality is not altered and affected due to the new changes in code. Regression testing provides testers with confirmation so that they can move the code to production.

Test Case Prioritization 

When taking a risk-based approach, testers select test cases that cover an app’s most affected areas by changes in code. They also rank them on a priority basis. Regression tests focus on product areas with an increased risk of quality issues. Testers should prioritize test cases according to critical and frequently used functionalities. When testers select test cases based on their priorities they can reduce the regression test suite, save maintenance time, and run regression tests faster and more frequently. 


Agile teams move faster than typical teams, while regression test suites can become a major burden for them. Although prioritizing regression tests is necessary for large projects, teams are forced to prioritize based on critical areas of a product that are error-prone. In today’s fast-paced technological era, businesses need quality software products that deliver a good customer experience and shorter release cycles, simultaneously. Hence it is necessary to ensure high-quality products that meet customer expectations. By adopting effective regression testing in an agile environment, QA teams ensure delivering products to the market in time, while ensuring all features are tested end-to-end for product quality assurance.