What is Regression Testing? Step-by-Step Guide

What is Regression Testing?

Do you know What regression testing means when it comes to software testing? 

Regression testing focuses on verifying that the changes such as bug fixes, feature improvements, and new feature additions do not adversely affect existing features or functionality. It is usually performed after a major code change or new software version has been developed, and it is used to make sure that existing features still work as expected. Regression testing helps to ensure that new changes do not introduce any new bugs or cause existing features to break.

Regression testing is also done when an application is deployed to a new environment, such as a different operating system or different hardware configuration. Additionally, regression testing should be performed periodically to ensure that changes made to the code over time have not caused any unintended consequences.

How to do Regression Testing

Let’s understand How to do Regression Testing with a real-world scenario.

Suppose you are running your own software development company and you get a new project. Next, your company starts implementing the product based on the requirements you take from the clients. At the same time, the testing team will start creating test cases according to the project requirements. After analyzing the requirements, your test team might come up with 1000 test cases. 

Once the product implementation is completed, you will test the product using those 1000 test cases and release the product to the client if the test results are successful. At this point, the client might request you to add a new feature. Now, your testing team has to write test cases to test the new feature. Let’s say your test team comes up with 50 test cases only to test the new feature functionalities. 

Now someone might think that testing only the new 50 test cases is enough before releasing the updated product to the client. This is where regression testing comes into play. When your development team adds new features to the product, it can break existing features as well. Therefore, you have to run not only the last 50 test cases but also the 1000 test cases you created for the original product. However, in case you don’t have that much time, you can only select test cases that test the features that can be impacted by the new feature development. This overall process is called regression testing. 

How Regression testing is performed can be broken into a few major steps. Now Let’s try to understand what these steps are.

1. Identify the requirements

Before performing regression testing, it is important to identify and document all the requirements that need to be tested. Identifying the test requirements should be started by understanding the business requirements. Testers can talk to stakeholders, review project documents, and analyze existing systems related to the product to identify what needs to be tested.

2. Define test cases

It’s highly important to understand the changes that will be added by the development team during a product milestone release. Using that knowledge, testers need to identify what functionalities are affected and which components are impacted by the recent changes. Using the collected information, testers can proceed with defining the required test cases. 

3. Select the test cases and set priorities

Once the requirements are identified and test cases are defined, we need to select the appropriate test cases that need to be executed under regression testing. Test Prioritization can be used to categorize the test cases into high, medium, and low-priority categories. High-priority test cases are the ones related to core functionalities and they are critical. These need to be executed first. 

4. Create a regression test suite

During this phase, we need to create a test suite with the selected test cases. When selecting the test cases for the regression test suite, we need to pay attention to factors,

• Identify the areas of the application that have recently changed.
• Identify the features or functionality that have not changed.
• Identify the test cases that have already been run for the features or functionality that have not changed.
• Identify the test cases that cover the areas that have recently changed.
• Identify any new test cases that should be added to cover the areas that have recently changed.

5. Execute the test cases in the regression suite

Next, the most critical phase of the process is the test case execution and recording of the test results. Execution can be done as a manual, automated, or hybrid process. 

6. Analyze the test execution results 

After the test execution, we need to analyze the test results and determine if there are any failures. 

Once you have collected your test results, you should review them for any differences between the expected and actual results. If any discrepancies are found, you should investigate further to determine the cause. 

7. Report test execution results

Once the regression testing is completed, we need to report the test results and share them with relevant parties. This helps to assess the quality of the product and identify any potential issues or areas of improvement. Additionally, sharing regression test results with stakeholders helps to build confidence in the product and ensure that any changes or modifications are properly tested.

Why is regression testing important?

Regression testing is important because it helps to ensure that changes made to a system or application do not introduce new bugs or cause existing features to break. It helps to ensure that the application continues to function correctly after any changes are made and that any new features are working as expected. Regression testing helps to maintain the quality of the product and ensure its stability.

Below are important benefits of conducting regression testing rounds in software testing.

• Ensures existing functionality is working as expected.
• Helps identify potential issues before new features are added.
• Helps in finding new bugs and regressions in existing code.
• Helps to track the impact of code changes on the existing system.
• Helps to make sure that the application is ready for release.

Tools for Regression Testing

Using tools for regression testing help automate the testing process, reducing the time and effort required to perform the tests, and increasing the accuracy of the results. Automation of regression tests also makes it easier to repeat tests and compare results over time. By using these tools, developers can quickly detect errors and fix them before they become a problem for users.

But selecting a tool depends on the project requirement. Let’s Identify the most widely used tools for regression testing.

1. Selenium

Selenium is a popular choice for regression testing because it is an open-source software tool that is highly flexible, easy to use, and supports multiple browsers and operating systems. Selenium can be used to automate a wide range of web applications and test scenarios, including form submission, data input, and automated navigation. It also allows testers to create and execute tests in multiple languages, such as Java, C#, Ruby, and Python. Additionally, Selenium is an ideal choice for regression testing because it allows for full test coverage and easy reporting of test results.

2. TestComplete

TestComplete is a comprehensive automation testing tool that makes it easy to create, maintain, and execute automated regression tests for desktop, web and mobile applications. It is a great tool for creating regression tests, as it can be used to create automated tests that are easy to maintain and execute. Additionally, it supports various scripting languages and can be integrated with other testing tools, such as Selenium and Appium. TestComplete also offers features such as record and playback, object-based identification, and data-driven testing, which are all beneficial for regression testing.

3. Ranorex

Ranorex is a powerful and easy-to-use regression testing tool that helps organizations quickly and accurately identify, isolate, and resolve issues when changes are made to applications. It is a comprehensive testing tool that enables teams to easily create, execute, and analyze tests across multiple platforms. With its drag-and-drop interface, Ranorex makes it easy to create automated tests that can be run on multiple devices and operating systems, providing a consistent and efficient testing process. In addition, Ranorex’s advanced analytics capabilities enable teams to quickly pinpoint and resolve issues. 

4. Watir

Watir is a powerful, open-source Ruby library that makes it easy to write automated tests for web applications. It enables testers to quickly create robust, browser-based regression tests and helps them to maintain them over time. With Watir, testers can easily create automated tests that simulate the user experience, allowing them to quickly identify any discrepancies between the expected behavior and the actual behavior of the application.

5. Katalon Studio

Katalon Studio is an automation testing tool that is used for functional and regression testing. It has an easy-to-use graphical user interface that makes it easy to create and maintain automated tests. It also has an extensive set of features and integrations that make it one of the most powerful and effective regression testing tools available. Katalon Studio supports a wide range of technologies including web, mobile, and API. It also has an intuitive and powerful script editor that allows users to write and debug automated tests quickly and easily.

Types of Regression testing

Different types of regression testing are necessary to ensure that the application is tested thoroughly and accurately. Each type of regression testing has its own purpose and focuses on a specific area of the application.

1. Corrective Regression Testing  

Corrective regression testing ensures that any changes or modifications to an existing system do not introduce new defects or cause existing defects to resurface. This testing typically involves running a series of tests on the system to ensure that all functionality is working as expected and that no new issues have been introduced. This type of testing is important in order to prevent defects from being propagated to the customer.

2. Retest-all Regression Testing

Retest-all regression testing is used to verify that the previously tested software does not regress when making changes or updates. It is a form of regression testing that checks the entire application, rather than just parts of the software, to ensure that no existing functionality has been broken or negatively impacted. This involves re-running all tests that have been performed previously to make sure that any new changes or additions to the software have not caused any existing features to regress. It is important to perform retest-all regression testing as part of a release process to ensure that any new changes or updates to the software do not negatively impact the software’s performance or lead to unexpected bugs or errors.

3. Selective Regression Testing

Selective regression testing is a method of regression testing in which tests are selected based on the changes made to the program. This type of testing is used to identify any problems that may have been caused by the changes. It is also used to identify any new interactions between components that may have been created by the changes. The selection process can be based on the code changes, the type of change, the risk associated with the change, or any other criteria. Selective regression testing is a cost-effective way to ensure that changes have not caused any unexpected problems.

4. Progressive Regression Testing

Progressive regression testing is a testing type that gradually evaluates the quality of a product by continually testing the existing code against changes in the system. This type of testing is used to ensure that the software is compatible with new features, bug fixes, and other changes. It is a continuous process of testing that begins with the most important features and progresses over time to test all areas of the system. 

5. Complete Regression Testing

With Agile practices, most companies prefer to engage in fewer but frequent product updates. But when it comes to real customer use cases it’s not always possible. Therefore companies are required to adapt quickly to ever-changing client requests.

When system updates happen on large scales complete regression testing will be performed. It is mandatory to perform complete regression testing as the root code has a considerable amount of change.

The goal of complete regression testing is to ensure that all existing functionality and features remain intact after any changes have been made. 

6.Partial Regression Testing

Partial regression testing is a software testing technique that involves running a subset of existing tests in order to verify that changes to a particular component or feature have not caused any unintended side effects. This type of testing is most commonly used when changes have been made to a system, but the system as a whole has not been completely overhauled. By running a subset of tests, developers can identify any potential problems that may have occurred as a result of the changes. Partial regression testing can help to ensure the system is still functioning as expected and reduce the risk of introducing new bugs or errors.

7. Unit Regression Testing

Unit regression testing is a type of software testing that verifies that individual units of code, or units, are working properly and as expected. It is a type of regression testing in which each unit of the software is tested to determine if it still functions as it did in its original version. This type of testing can help to identify errors and defects in the code and to ensure that changes made to the code do not adversely affect the functionality of the software. Unit regression testing is typically conducted by developers as part of their development process and is done in isolation, meaning that the code is tested without being integrated with other code.

Conclusion

In this article, we answered “what does regression testing mean”, and “How to carry out regression testing”, Why is regression testing important, what Tools of regression testing, and what types of regression testing? I hope this knowledge will be helpful to carry out proper regression testing in your workplace.