Have you ever thought about how your favorite apps and software continue to improve with every update? Imagine developers working tirelessly, testers diligently checking for issues, and new features being integrated constantly.
However, each change brings the essential responsibility of making sure everything continues to operate smoothly without any unnoticed bugs slipping through. This is where regression testing becomes crucial in maintaining the system’s stability!
In this blog post, we’ll dive deep into what is regression testing, exploring its test cases, various types, tools, and all the key details you need to know. Let’s get started!
What Is Regression Testing?
Regression testing is a software testing method that involves re-executing both functional and non-functional tests to confirm that an application continues to perform as expected after code changes, updates, revisions, improvements, or optimizations. This testing is crucial in the software development process, as it helps developers identify unforeseen issues in the application that may result from modifications or expansions of the existing codebase.
Regression testing ensures the overall stability of a software application by monitoring the functionality of existing features. It is a crucial step after any code modification, ensuring that the system remains reliable and can handle continuous improvements.
Is Manual Regression Testing Possible?
Yes, regression testing can be conducted manually. This process involves retesting the altered parts of a software application to confirm that the changes haven’t adversely affected existing functionalities.
While manual regression testing is feasible, it can be labor-intensive and prone to errors, particularly in large or complex systems. For this reason, using automated regression testing tools is advised to enhance efficiency and accuracy.
Regression Testing Examples
Let’s say you’re developing an image and video editing application. After completing the core features, you conduct regression testing with 1,000 test cases to ensure everything is functioning correctly. Once the tests are successful, you deliver the application to the client.
Later, you realize that the application could benefit from new features to improve customer satisfaction. After adding these features, you need to re-run regression testing. You create 100 new test cases for the updates and re-run the original 1,000 to ensure that the core functionalities are still working as intended.
This is a common example of regression testing in real-world scenarios. It’s valuable for identifying potential issues that may arise from code changes, though it requires careful preparation and effort. Next, we’ll discuss the best situations for performing regression testing.
When to Perform Regression Testing?
Ideally, regression testing should be conducted whenever changes are made to a system and the code is modified, whether it’s adding new features, fixing bugs, or improving performance. It’s appropriate in situations like:
- Adding a new feature or functionality: For example, if you’ve built a website with a login feature that only allows users to log in via email, and then you add an option to log in via Facebook.
- Changes in requirements: For instance, if you decide to remove the “remember password” feature from the login page that was previously available, regression testing is necessary after such changes.
- Fixing defects or patches in the codebase: For example, if a tester reports that the login button is broken, once the developers fix the issue, the login button is retested for expected behavior, and other related functionalities are also tested.
- Resolving performance issues: For instance, if a page initially takes 5 seconds to load and the loading time is reduced to 2 seconds, regression testing ensures that the performance fix doesn’t affect other parts of the application.
- Making environment or configuration changes: For example, updating the database from MySQL to Oracle requires regression testing to confirm that the application works correctly with the new configuration.
Advantages and Disadvantages of Regression Testing
Let’s take a look at the various advantages and disadvantages of Regression Testing.
Advantages
- Confirms that changes in the code don’t negatively impact other functionalities.
- Ensures that previously resolved issues don’t reappear.
- Acts as a risk mitigation measure during testing.
- Simple to learn, comprehend, and evaluate.
Disadvantages
- Regression testing can be very time-consuming without automation.
- It needs to be done for every minor code change.
- The repetitive nature of the process can impact an agile sprint.
- Requires the creation of complex test cases.
How to Conduct Regression Testing?
Usually, there is no standardized approach for conducting regression testing. However, there are several commonly used regression testing methods that a QA analyst should consider.
Step 1: Selecting Regression Tests
As implied by the name, this step involves choosing the test cases that need to be retested. Instead of running the entire test suite, you focus on test cases related to the module where changes have been made to the source code.
Ultimately, you categorize the test cases into (I) Reusable Test Cases and (ii) Obsolete Test Cases. Reusable Test Cases will be retained for future regression cycles, whereas Obsolete Test Cases will be excluded from upcoming testing cycles.
Here are some tips for identifying reusable test cases:
- They are prone to frequent errors.
- They check the functionality of the application.
- They involve features that users can see.
- They pertain to recent changes in the source code.
- They have previously been executed successfully.
- They have failed in earlier testing phases.
- They are related to integration aspects.
- They involve boundary-value conditions.
Step 2: Estimate the Time for Executing Test Cases
The next step involves estimating the time required to execute the selected test cases. Factors influencing the execution time include the creation of test data, regression test planning by the QA team, and the review of all test cases.
Step 3: Determine Which Test Cases Can Be Automated
In this step, based on exploratory testing results, the QA team identifies which test cases can be automated. Automated test cases are quicker than manual testing and enable the reuse of the same script multiple times. Thus, categorize the test cases into two groups: (i) manual test cases and (ii) automated test cases.
Step 4: Prioritizing Test Cases
In this step, you collect all the test cases and rank them as high, medium, or low priority. You will then execute the high-priority test cases first, followed by those of medium and low priority. Prioritization is based on the product’s functionality and user impact.
Here’s the priority structure:
- Priority 0: The most critical test cases covering core functionalities.
- Priority 1: Important features, though not part of the core functionality.
- Priority 2: Test cases addressing technical debt.
Step 5: Executing Test Cases
At this stage, you execute all the test cases individually to verify whether the product functions as expected. Depending on your needs, you can choose between manual testing or automation. For automated regression testing, tools such as Selenium, QTP, and Watir can speed up the execution of test cases.
You should now understand how to perform regression testing. Next, we’ll explore the popular methods used for regression testing.
Regression Testing Methods
There are four main regression testing methods commonly used:
- Regression Test Selection: In this method, you choose which test cases need to be re-tested.
- Test Case Prioritization: It involves collecting all test cases and ranking them in priority order.
- Retest All: This approach requires re-testing the entire regression test suite.
- Hybrid: This method combines both Regression Test Selection and Test Case Prioritization techniques.
Among these methods, the hybrid approach is the most effective. Instead of selecting all the necessary test cases at once, you can execute them based on whether you start with regression test selection or test case prioritization. This approach saves significant time and effort.
How to Develop a Successful Regression Testing Suite?
A regression testing suite consists of a collection of test cases aimed at verifying that your software continues to function correctly following any changes or updates. Here are five steps to creating an effective regression testing suite.
Step 1: Prioritizing Regression Tests
To build an effective regression testing suite, it’s crucial to prioritize test cases. Start by giving the highest priority to test cases for core features, such as the back-end engine, API, and database. The next priority should be assigned to the remaining parts of the application, followed by test cases related to technical debt.
Step 2: Developing a Smoke Test
Assign a smoke test label to the high-priority test cases and execute them daily, every two weeks, or with each new build. You may also opt to automate these test cases for greater efficiency.
Step 3: Utilize Manual Testing
Some functions that users interact with regularly are not overly complex and don’t require automated workflows. In these cases, manual regression testing is sufficient to address these scenarios effectively.
Step 4: Test the Integrations
Run a regression test suite that includes integrations such as APIs, backend engine functions, database connections, and data feeds. Additionally, validate the integrated processes necessary for the application.
Although users don’t interact directly with these functionalities, they are essential for the app’s operation. This integration testing ensures that all business logic is functioning correctly.
Step 5: Consider Performance
With every release, your application’s performance should either improve or remain consistent. Therefore, always perform a performance test on your product or app before it is released to the market.
Types of Regression Testing
Various types of regression testing are explained as follows:
- Corrective
Corrective regression testing is suitable when there have been no changes to your application’s source code. The focus is on verifying that the current system is functioning correctly by testing existing functionalities and their associated test cases, rather than creating new ones. - Progressive
Progressive regression testing is ideal for adapting testing requirements and creating new test cases. This type of testing is particularly useful when introducing a new component into the system, as it helps ensure that the changes do not negatively impact existing components. - Selective
As the name suggests, selective testing involves limiting test coverage to a specific set of pre-existing test cases. This means you only test a few chosen components rather than retest the entire system. - Partial
Partial testing is conducted to understand the impact of adding new components to the system. For example, it checks whether a new line of code affects the system. Unlike selective testing, partial testing involves testing both the new functionalities and the existing ones together, allowing you to observe their combined impact. - Complete
Complete testing involves evaluating the entire system at once. It is akin to acceptance testing and is used to determine whether the user experience is affected by the addition of one or more modules. This type of testing is usually performed just before the final release of the product. - Retest- All
The concept of Retest-All testing involves re-running all the test cases in the suite to ensure that no new bugs have been introduced due to changes in the application’s source code. This approach requires significantly more time and effort from the QA team compared to other methods.
Now that you understand the different types of regression testing, it’s important to note that in today’s automation era, many rely on various tools for regression testing. Next, we will explore some of these tools.
Top Regression Testing Tools
Let’s explore some of the leading regression testing tools that can streamline your testing process and enhance software quality.
- Selenium
Selenium is one of the top regression testing tools you might be familiar with. It’s often the go-to choice for browser-based or cross-platform regression testing. This tool offers automated test scripts using datasets and is particularly well-suited for large-scale quality assurance testing conducted by experienced testers. - Katalon Studio
Katalon Studio offers a comprehensive solution for regression automation testing, designed to simplify the process for novice testers. It serves as an all-in-one tool for testing web services, web applications, and mobile apps. Additionally, Katalon Studio includes features for reporting and advanced analytics. - IBM Rational Functional Tester
Rational Functional Tester (RFT) is an automation tool designed to support various types of testing, including regression, functional, and data-driven testing. It is versatile in testing different applications such as web apps, .NET, Java, SAP, and emulator-based apps. RFT aims to simplify the testing process for testers globally. - Watir
Watir is an open-source regression testing tool written in Ruby, designed to make writing test cases easy to read and understand. It features a lightweight and flexible user interface and provides interactive capabilities for website testing. Its user-friendly nature and effectiveness contribute to its widespread popularity. - Apache JMeter
Apache JMeter is an open-source regression test automation tool developed by Apache for measuring test case performance. Written entirely in Java, JMeter offers key features such as load and performance testing, service performance measurement, and a regression testing suite for end users. - AdventNet QEngine
AdventNet QEngine is a well-known regression automation testing tool widely utilized for web applications. It is comprehensive, platform-independent, and user-friendly. Additionally, AdventNet QEngine supports multiple platforms, allowing scripts recorded in Windows to be replayed in Linux. - Subject
Subject7 is a popular cloud-based regression automation testing tool used at the enterprise level for desktop, web, and mobile applications. It supports high-scale parallel execution and is compatible with public, private, and hybrid cloud environments. From both technical and financial perspectives, the tool is notable for its effectiveness and value. - TimeshiftX
TimeShiftX is an advanced regression automation testing tool that is highly appreciated by QA teams. Its unique selling point lies in its ability to shorten test cycles and reduce resource needs, giving companies a competitive edge. Additionally, it facilitates faster software releases, which contributes to its popularity among testers. - Cerberus Testing
Cerberus Testing is a fully open-source regression testing automation tool that supports web and mobile APIs and requires minimal coding. Available in the cloud and accessible via a web interface, it doesn’t demand advanced development skills. The tool’s reusable test modules and test data contribute to its popularity among testers. - Testsigma
Testsigma is an ideal automated testing tool for regression testing. It features scriptless test cases written in plain English, making it user-friendly. Additionally, Testsigma supports CI/CD workflows with tools like Jenkins, JIRA, and Slack. It also allows you to write custom functions and define prerequisites for regression test suites.
Regression Testing Best Practices
To ensure effective regression testing and maximize its benefits, it’s crucial to follow best practices. Here are some key practices that can help you achieve optimal results:
- Staying Updated with the Latest Regression Suites
Just as with any technology, it’s important to stay updated with the latest regression testing suites. To ensure effectiveness, focus on both functional and non-functional requirements. The QA team should prioritize executing the high-priority and high-value test cases first. - Understanding Every Change Hands-On
In software development, change is constant, so having direct knowledge of every modification is essential. Regularly engage with developers and testers to stay informed about the latest updates and immediate changes. This helps in planning testing effectively and ensures alignment with the app or product release schedule. - Assigning Grades to Test Cases
To achieve success in regression testing, it’s crucial to assign grades to your test cases. Evaluate their business impact across different platforms and categorize them into high, medium, and low priority based on these assessments. This approach helps you identify and address various roadblocks, ensuring that testing is conducted effectively according to the requirements. - Understanding the Scope of Testing
Before initiating the regression testing process, it’s crucial to grasp its scope. Each testing project can differ in scope, duration, and objectives. By understanding these variations, you can plan and execute your regression cycle more effectively. - Automate the Right Test Cases
To leverage automation effectively, it’s important to use it wisely. Begin by identifying which test cases are suitable for automation and which are not. By automating the appropriate test cases, you can boost productivity and save valuable time. - Track ROI
ROI (Return on Investment) is a crucial metric for evaluating the success of your regression testing efforts. QA teams should continuously monitor ROI using advanced analytics and reports from automation tools. This approach provides insight into actual performance and highlights areas that need improvement.
Regression Testing and Agile Methodology
In agile methodology, which emphasizes incremental and iterative development, software or product development occurs over short cycles known as sprints. Each sprint introduces changes to the source code, such as new features or updates. This is where regression testing becomes essential.
Agile teams should start preparing the regression test suite early in the product development cycle and maintain it through to the final deployment. In agile practices, regression testing can be approached in two primary ways:
- Sprint Level Regression
This type of regression testing is used to assess the impact of new features or updates introduced in the current sprint. You select test cases based on the changes made during the sprint to evaluate their effects on the product. - End-to-End Regression
In this approach, you re-run all completed test cases to verify that the core functionalities of the product continue to perform as expected. This ensures comprehensive testing of the entire system.
In agile methodology, where development occurs in short sprints, frequent regression testing is essential. Performing this testing manually can be cumbersome for QA experts, so many teams turn to automation. Automated regression testing not only speeds up the execution process but also helps in quickly identifying recurring defects.
Challenges in Regression Testing
The primary challenges in regression testing include:
- Test suites expand in size with each regression run, and running the entire suite can be constrained by time and budget limitations.
- Achieving optimal test coverage while reducing the size of the test suite remains challenging.
- Deciding how often to conduct regression tests, whether after every change, build update, or a series of bug fixes, is not simple.
Conclusion
Organizations could have prevented these issues by performing regression testing before implementing updates or adding new features. This example highlights the critical role of regression testing in modern software development. Regression testing is essential for delivering high-quality, reliable applications that foster user loyalty. Considering these aspects, this article offers a thorough overview of regression testing, including its types, tools, methods, and other key details you need to know.
If you’re interested in learning more about regression testing or need assistance with testing your products, feel free to connect with us . We’re here to guide you through the testing process with our expertise and ensure a smooth development journey.
