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What is Regression Testing?

What is Regression Testing?

Do you know what is regression testing? Whenever changes were made to software, developers needed a way to ensure that these modifications didn’t introduce new errors or regress the system to a less stable state. This is the correct situation where Regression testing comes into play. In this blog, we will discuss its importance, and how it’s done.

We will be discussing the following topics:

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What is Regression Testing?

Regression testing is a type of software testing usually performed to verify that the recent modifications made to the software are not producing any issues or disruptions to the existing features. Regression testing is typically conducted after implementing new changes in the code. It is like double-checking your favorite recipe every time you make it, ensuring that any new changes don’t accidentally ruin the dish.

Regression testing is usually done by quality analyst (QA) teams to optimize code and maximize test efficiency. It is an excellent choice for automation testing because it involves repeatedly executing a set of test cases without manual intervention.

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Why Do We Need Regression Testing?

Regression testing is important because changes in one part of the code might unintentionally mess up something else. It helps us catch these issues early, preventing the introduction of problems and keeping the software stable and reliable. It’s a bit like making sure your favorite dish tastes just as good every time you cook it!

How is Regression Testing Done?

Regression testing involves several steps to ensure the stability and integrity of software after modifications or updates. These repetitive steps help validate the unchanged functionalities and detect potential issues introduced by new changes. Given below are the steps that should be followed for performing regression testing:

How is Regression Testing Done

Step 1: Understand the Existing Functionality

Have a clear understanding of the existing features and functionalities of the software application. Create a comprehensive test suite that covers all critical areas of the application. A test suite refers to a collection or set of test cases, test scripts, or test scenarios that are designed to evaluate various aspects of a software application.

Step 2: Identify, Automate, and Execute Test Cases

Select test cases from the existing test suite that are relevant to the areas of the code that have been modified or enhanced. Then, prioritize test cases based on the criticality of the functionality they cover. 

Whenever possible, automate the selected test cases to speed up the regression testing process. Automated tests can be set up by creating script-based instructions or using testing tools like JUnit, TestNG, etc., to systematically execute predefined test cases, providing quick and consistent validation of software functionality. Automated tests can be executed quickly and consistently. Ensure that the tests cover not only the specific changes but also related functionalities.

Step 3: Compare Results

Compare the test results with the expected outcomes recorded during the initial testing. Then, identify any discrepancies or failures.

Step 4: Report Defects

If any defects or issues are identified, report them to the development team including detailed information or any relevant logs.

Step 5: Fix Defects

Developers address and fix the identified defects. Once fixed, the code is retested by the development team.

Step 6: Re-Run Regression Tests

After the defects are fixed, re-run the affected test cases as well as related test cases to ensure that the changes did not introduce new issues. Repeat the regression testing process whenever there are new code changes or updates to the software. The frequency of regression testing depends on the development cycle and the volume of changes.

Step 7: Maintain Regression Test Suite

Regularly update and maintain the regression test suite to include new test cases for any added features or changes in requirements.

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Examples of Regression Testing

In this section, we will understand the two examples where regression testing can be applied:

1. Example: Database Migration


A software application uses a specific database structure.

Database Migration:

The application undergoes a database migration to a new version or a different database system.

Applying Regression Testing:

Regression testing is conducted to confirm that the database migration did not impact the application’s functionality and that data is still stored and retrieved correctly.

2. Example: Mobile App Update


A mobile banking app allows users to check their account balance and transfer funds.

App Update:

An update has been released to add a new security feature and improve the fund transfer process.

Applying Regression Testing:

Regression testing is performed to ensure that the existing features (checking account balance and fund transfers) still work seamlessly after the update and that the new security feature functions as intended.

Regression Testing Techniques

Let us see a detailed explanation of regression testing techniques that are used in software development:

  • Re-Test All: Test everything, just like before, to make sure nothing is broken.
  • Selective Testing: Pick and test only the things that might be affected by recent changes.
  • Test Case Prioritization: Test the most important things first, so if there are issues, they’re found quickly.
  • Test Case Automation: Use machines to run tests automatically, especially for tasks that are boring or take a long time.
  • Test Case Impact Analysis: Look at where the changes were made and test those areas more.
  • Continuous Integration/Continuous Deployment (CI/CD) Pipelines: Make tests part of the process every time something new is added to the software.

Difference Between Retesting and Regression Testing

Retesting and Regression Testing are both essential components of the software testing process, aiming to ensure the quality and reliability of an application. The table below highlights the key differences between retesting and regression retesting:

ParametersRegression TestingRetesting
Test CasesSelected from the entire test suite, emphasizing both modified and related functionalities.Selected based on the specific defect being fixed, re-executing the same test cases that initially identified the defect.
FrequencyTypically performed after every code change or addition of new features.Performed as needed, specifically after a defect has been fixed.
Time and EffortMay require more time and effort due to the comprehensive nature of testing.Quicker than regression testing.
Test EnvironmentConducted in an environment that closely resembles the production environment.Conducted in a controlled environment with specific test data.
Testing CycleIntegral part of the continuous integration and continuous deployment (CI/CD) process.Can occur at different stages of the software development life cycle, often after defect fixes.

Top Tools for Regression Testing

The choice of tools for regression testing depends on factors such as the type of application, testing requirements, and the development environment. Here are some popular regression testing tools:



Selenium is a free tool that helps automate tasks on the internet, especially websites. People often use Selenium WebDriver to make computers do tasks on websites automatically, and it’s frequently used to check if a website still works correctly after changes are made—kind of like making sure everything is still in order. It works with different computer languages like Java, C#, Python, and more.

Katalon Studio

Katalon Studio

Katalon Studio is an integrated test automation tool that is widely used for web, mobile, and API testing. It provides a comprehensive platform for creating and executing automated tests. Katalon Studio supports web testing for various browsers, making it suitable for testing web applications.



Appium is an open-source automation framework that allows automated app testing for mobile applications (Android and iOS). Appium supports multiple programming languages, making it a versatile choice for automation across different development stacks.

IBM Rational Functional Tester

IBM Rational Functional Tester

IBM Rational Functional Tester (RFT) is a tool created by IBM to automatically test software programs. It’s mainly used to check if web applications are working correctly. This tool can be applied to different types of software, like those made with Java, .NET, SAP, and even programs that use terminal emulators. Its main job is to make sure that when changes are made to a program, it doesn’t cause any new issues and that everything keeps working as it should.

Challenges in Regression Testing

In this section, we will understand the various challenges that can occur during regression testing.

  • Test Environment Stability: Ensuring a stable and consistent testing environment is a challenge, as changes in configurations of environment may impact the reliability of test results.
  • Time and Resource Constraints: Regression testing can be time-consuming, especially in large and complex applications. Limited resources, tight deadlines, and pressure to release quickly may lead to incomplete regression testing.
  • Integration Issues: When multiple components or modules are integrated, unexpected issues may arise. It’s important to ensure that the integration points are thoroughly tested to identify any regressions.
  • Automation Maintenance: Maintaining and updating automated test scripts can be challenging, especially when dealing with changes in the application’s structure or functionality.

Applications of Regression Testing

Regression testing is applicable across various domains and types of software. Here are some common applications of regression testing:

  • Money Software: In the finance world, where money is involved, it’s crucial to have software that works accurately. Regression testing prevents mistakes in calculations or transactions.
  • Health Software: Software used in healthcare, like patient records, needs to be error-free. Regression testing ensures that any updates don’t mess up important information.
  • Video Games: Video games get updates and new features all the time. Regression testing ensures that these changes don’t create new problems or glitches in the game.
  • Business Systems: Big companies use systems that connect different parts of their work. Regression testing makes sure that changes in one area don’t mess up how everything else works.

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The future of regression testing is all about changing and getting better to keep up with how software development is always evolving. As technology advances, regression testing will play a crucial role in maintaining the quality and reliability of software applications, contributing to the delivery of successful and user-friendly products.

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