Types of Regression Testing

Regression testing has become increasingly important in software engineering as the field has become more complex and expensive. While the introduction of libraries, cloud-based services and open-source frameworks were meant to decrease development time and costs, ironically, the chances of something going wrong expands with more components added into the mix. This is where regression testing comes in. It helps QA engineers make sure that none of those components gets broken whenever a system undergoes even a minor software update.

In this article, let's dive into the different types of regression testing and which type is more suitable for specific scenarios.

What is Regression Testing?

Regression testing is a software testing approach that ensures that previously developed and tested software functions correctly after recent changes or modifications. These changes could include bug fixes, updates, or new features added to the software.

In essence, regression testing involves re-executing test cases and comparing the new results with the previously expected outcomes. If the outcomes are consistent, it indicates that the changes have not adversely affected the existing functionality. However, if discrepancies are found, it could indicate a problem introduced by the changes, requiring further investigation and potential fixes.

Regression testing can be performed manually or with automation testing tools. However, automated regression testing is often preferred, as it can save both time and resources, reduce human error, and allow for more frequent and consistent testing, especially when dealing with large and complex software systems.

Different Types of Regression Testing in Software Development

Different types and forms of regression testing exist, and picking the right one can be a challenge. To make an informed decision, consider your software development life cycle and the particular updates you plan to introduce. Since software development and testing are interconnected, the regression testing technique you select should align with your development process. Below are some common regression testing methods:

1. Corrective Regression Testing

Corrective regression testing is a type of software testing performed to ensure that a software system or application is still functioning correctly after a bug or defect has been fixed. Here, the focus is on retesting the areas that were affected by the bug rather than testing the entire system from scratch.

One advantage of Corrective regression testing is that it can be performed using the existing test cases that were used to test the system before the bug was discovered. This eliminates the need to create new test cases, saving time and effort.

2. Complete Regression Testing

Complete regression testing is a software testing process in which the entire software application is tested thoroughly to ensure that any changes or updates made to the system do not negatively impact its existing functionality. This testing process aims to identify any new bugs, errors, or issues that may have been introduced as a result of changes to the system or its environment.

During complete regression testing, testers typically execute all test cases, scripts, and scenarios that have been created for the application, including those that cover previously tested features and functions. The goal is to make sure that changes to the system have not caused any unexpected issues or broken any previously functioning features.

Complete regression testing is a time-consuming and resource-intensive process, but it is important for ensuring the overall quality and reliability of the software application. By executing all test cases, developers can have confidence that the application has not been negatively affected by any changes and that it continues to function as expected.

3. Partial Regression Testing

Partial regression testing is performed to verify the behaviour of a system after the new code is integrated with an existing codebase. This type of testing aims to identify any potential issues that may arise from changes and make sure that the system is functioning as expected after introducing new code.

Partial regression testing typically involves the selection of specific test cases that are relevant to the changes made to the system. This permits testers to focus their efforts on the areas of the system that are most likely to be affected by the new code.

One major advantage of partial regression testing is that it can be performed quickly and efficiently compared to complete regression testing. This is because only selected test cases need to be executed, and not all the test cases are created for the system.

4. Unit Regression Testing

Unit regression testing is a critical aspect of unit testing, which focuses specifically on the code units or modules of software applications and ensures that any dependencies associated with them are blocked out during testing.

The main objective of unit regression testing is to identify and address any recurring defects or issues that may be present in the code units. This allows to improve the reliability of the code and make sure that it performs as expected. Additionally, this testing approach also considers the criticality of certain features in the software application, ensuring that they are functioning as intended.

During unit regression testing, individual code units are tested repeatedly to ensure that they continue to perform as expected, even after changes have been made to the codebase. This helps to make sure that the code remains stable and reliable and that any changes made to it do not negatively impact its performance.

One of the key benefits of unit regression testing is that it helps to deliver useful units of code that enhance and add value to the overall application. By identifying and addressing issues with the code units, developers can ensure that they are delivering high-quality code that meets the requirements of the users and performs as intended.

5. Retest-all Regression Testing

Retest-all regression testing is a comprehensive and rigorous testing approach that involves verifying all of the system's specifications from the beginning. It aims to examine every small change that the software has gone through since its initial development. This sort of testing is usually carried out when other regression tests have failed to pinpoint the root cause of a problem, as developers suspect that the issue may have originated prior to the recent code modifications.

6. Selective Regression Testing

Selective regression testing is a type of software testing carried out to find the behaviour of the code when new code is introduced into an existing codebase. The aim of this form of regression testing is to reduce the effort and cost required for retesting by using a subset of existing test cases. This subset is selected based on the likelihood of the new code affecting the functionality of the tested software.

For instance, when an update is made to a program, such as the addition of new functions or variables, a test unit is re-run as part of selective regression testing. This approach enables testers to quickly identify any issues due to the new code and verify that the existing functionality of the program has not been affected. By using this approach, developers and testers can effectively manage changes to the codebase while ensuring that the software remains reliable and bug-free.

7. Progressive Regression Testing

Progressive regression testing is a form of regression testing that can provide more valuable results when targeted modifications are made to a program, and new test cases are created. By conducting this type of testing, you can ensure that any changes made to the program do not compromise the elements present in the previous version.

This testing approach involves running a set of existing test cases on the latest version of the program, followed by adding new test cases that target the specific changes made. As a result, it can detect any unexpected issues or bugs that might have been introduced during the modification process. Progressive regression testing can be a useful tool in software development because it can help identify and resolve problems early on in the development cycle, minimizing the risk of delays and costly errors.

How to Enhance the Efficiency of Regression Testing

The key to improving regression testing effectiveness lies in employing suitable automation tools and adhering to best practices. Let's explore some popular tools that can be considered for the testing purpose:

1. Selenium

A widely favoured option, Selenium offers numerous advantages, such as extensive libraries, open-source frameworks, and support for C#, Java, Ruby, and Python. It's a reliable choice. In fact, LambdaTest is an excellent choice for Selenium-based regression testing due to its various features and benefits.

Firstly, it offers a cloud-based platform that provides seamless access to a wide range of browsers, operating systems, and devices, ensuring comprehensive testing coverage. Secondly, LambdaTest is a unified digital experience platform that offers real-time testing capabilities, which enable testers to interactively debug and diagnose issues during test sessions.

Additionally, LambdaTest supports parallel test execution, which helps to reduce test cycle times and accelerate the overall testing process.

LambdaTest also provides a straightforward integration process with popular CI/CD. Lastly, LambdaTest offers a detailed reporting system that provides valuable insights into test results. These reports include screenshots, logs, and videos, making it easy for teams to analyze test outcomes and identify any regressions quickly.

To experience the benefits of LambdaTest for your own regression testing needs, don't hesitate any longer. Sign up for a free trial today itself and take the very first step towards achieving a more efficient, reliable, and streamlined testing process for your web applications. Discover how LambdaTest can revolutionize your testing experience and ensure the highest level of quality for your end users.

2. TestComplete

An excellent tool for parallel testing, TestComplete employs automated builds, eliminating the need for manual intervention. It's well-suited for web, mobile, and desktop apps.

3. TestDrive

Focusing on speed and simplicity, TestDrive is flexible, easily deployable, and dynamic. It emphasizes automation but also allows for some manual testing options.

4. TimeshiftX

Acting as your virtual time machine, this app enables temporal testing by manipulating virtual time, allowing you to review and test all app changes retrospectively.

These testing tools are among the top choices. Give them a try to determine if they're suitable for your project.

Conclusion

Regression testing is an essential aspect of software testing that ensures the quality and stability of software products. As software continues to evolve and become more complex, regression testing becomes even more important in ensuring that changes are delivered quickly and without compromising the quality of the software. The use of different types of regression testing and identifying which tests to prioritize is key to ensuring efficient and effective testing. Therefore, consider implementing these testing types in your business today to reach unprecedented levels of success.