What is Regression Testing?

What is Regression Testing? – A short introduction

Regression Testing is not a regular part of software testing. It becomes an essential addition when a system has had bug fixes, upgrades, or enhancements.

Software is regression-tested to ensure that the system works as it should and that any changes have not impacted performance. In addition, the testing helps confirm the overall stability of an application. Some of the system’s existing test cases are rerun as part of the tests.

How do you determine the scope or what should be included in a regression test? First, testers examine the entire application, not just the parts with code changes. Second, it is necessary to perform tests for the existing system and the newly developed features to determine if everything remains stable and operational.

Defining the Scope for Regression Testing

Reasons for performing regression testing are widely understood. Still, the biggest challenge before testing can begin is defining the scope and determining how much testing is enough.

The tester will study the requirement changes in black-box testing, get an understanding of the impact, and then plan the testing. However, they remain unaware of all the dependencies and relations, so the regression suite is built on assumptions. Categorizing the regression test into two steps proves helpful:

  1. The first is to ensure the new changes do not break any of the related components. For example, if the requirement is to add new password criteria, the functional testing would include tests to check if new passwords match the defined criteria. The regression must consist of checks to discover if users can still log in using their existing passwords without any issue.
  2. The second step is to check and test all the critical areas, even though they may seem unaffected. Still, since the regression is built on assumptions, it’s advisable to run checks for the key areas in every round of assessments.

What is Regression Testing?

When is the right time for Regression Testing?

Regression testing is required when coding or any other changes are made to the already released software. It is not part of an application’s initial testing.

Some circumstances that require regression tests include:

  1. Bug Fixes – As part of the bug cycle, after a developer acknowledges and fixes the bug, it is retested before closure. During bug retesting, the primary focus remains on testing the fixed bug and ensuring the fix is working as expected. In addition to the bug retest, teams also run a regression check to eliminate issues beyond the bug’s scope.
  2. Feature Enhancement – Enhancement is a continuous process that drives any software. Any feature addition or changes to existing flows requires code modification. Before a feature is approved for sign-off, it undergoes thorough testing. The teams also run regression tests to confirm that the new feature is good to go and has no impact on the existing product.
  3. Environment Upgrade – The system could be impacted during an environmental upgrade but changes might not be visible. In such scenarios, running functional tests becomes less necessary, but running all regression checks is essential. The team usually runs a full regression test suite to ensure that issues haven’t arisen because of the upgrade.
  4. Platform Migration – Platform migration is yet another area where the changes might not impact the front-end users directly, but ensuring the migration hasn’t broken anything remains the top priority for any tester. A test suite consisting of all functional and non-functional tests is run as part of regression.
  5. New Integration – When the requirement calls for any new integration, the testing team establishes a plan to test the new integration. At the same time, a well-laid regression suite is planned for testing all other components directly or indirectly impacted by the integration.

Should Regression Tests be automated?

Due to its nature, regression involves performing repetitive tasks and is very time-consuming, so teams generally prefer to automate. Thus, regression test suites are created once, then rerun before each release. But, automation is not without time-consuming tasks because maintaining the scripts requires frequent updates.

Regression testing requires existing test cases to be rerun, and it doesn’t require much effort to create new ones. The need for regression testing to be automated depends on the type and size of the software. For products or applications undergoing frequent feature upgrades, automating proves to be an unhelpful way to test. In such cases, a set of regression test scenarios are identified and run manually during each QA cycle.


Regression testing ensures that software is examined thoroughly and that all pieces function flawlessly, despite any number of changes, with minimal maintenance required.

Priya Rani

Priya Rani

An Enthusiastic QA Expert who loves to share knowledge and experience through blogging.