Regression Testing in Software Testing: Ensuring Quality
Software uses large, complex codebases that are difficult to change. It's because even minor code changes can cause new bugs and problems. While smart checks like unit tests are helpful, regression testing in software testing is a holistic way to ensure these changes are problem-free. Moreover, today's guide aims to explain regression testing in detail.;
What is Regression Testing?
Regression testing is a crucial part of software development. It involves re-testing existing features to check whether the latest code updates have caused problems or bugs. It helps to recognise and fix sudden bugs, ensuring software steadiness and allowing the development team to deliver quality products.
Why is it Important?
Regression testing in software testing is crucial for agile development with regular code updates. Regression testing ensures that regular updates don't break the software's existing features and functions by re-running tests for known bugs and issues. This results in benefits like faster app development and fewer glitches that help create a positive user experience.
Examples of Regression Testing in Software Testing
It's now time to understand regression testing with the help of an example. Suppose a software firm launches a new graphic designing tool in the market. Before release, the firm used 500 regression test cases to check the tool's performance and issues. After the positive test results, the company launched its tool in the market.;
After some time, new features were added, which required another 150 regression test cases. Even though the team ran regression testing for these 150 new test cases, they re-ran the original 500 cases to ensure the performance stayed intact.
So regression testing in software testing includes re-running old tests every time a new code is added. Even though it's tiring, finding software bugs and preventing new codes from creating issues is crucial.
Types of Regression Testing
Regression testing in software testing is vital for software development and ensures that new codes don't cause performance issues. But regression testing isn't just a single process. It comprises several types designed to handle various needs and test levels. Now, we will study the different types of regression testing so you can choose the right one for your needs.
- Complete Regression Testing:- This involves re-running all past test cases, including those unrelated to the recent update. It's a lengthy and time-consuming process, especially if you are working on a large project. This type of regression testing is generally done after a major software update or substantial changes in the software.
- Partial Regression Testing:- Such testing aims to test only the part of the system that could be affected by the new code update. Partial regression testing aims to examine dependent functions and modules and is more efficient than complete regression testing. This type of testing is used for minor updates and patches.
- Selective Regression Testing:- It's a more strategic approach towards regression testing in software testing. Instead of testing all potentially affected areas, selective regression testing studies the code updates and their possible impact to choose a subset of test cases. However, this approach needs a deep understanding of the software's architecture.
- Focused Regression Testing:- This is the most concentrated approach in regression testing. It aims primarily at the code's areas that have been modified or updated. It's a great way to perform quick checks during development which helps ensure that recent updates don't cause functionality issues, regression, and bugs in the system.
- Unit Regression Testing:- This type of regression testing in software testing focuses on a particular code units or components. It helps to ensure that changes to specific modules or functions don't affect their behaviour or cause regression during the interaction with other units. This approach helps to quickly detect the source of problems after code updates or revisions.
- Integration Regression Testing:- Such approach aims to test interactions between different modules and components after changes have been made in the codes. It helps to ensure that these integrated parts are still working perfectly together. It helps to ensure that different software parts work perfectly together as expected.
- Progressive Regression Testing:- This is a constant approach that helps to ensure software quality as a system evolves. As new features are added to the software, regression tests are combined into the suite. This suite is then run regularly to avoid issues. It's like a growing safety net to detect and catch problems early.
- Automated Visual Regression Testing:- Instead of monitoring software codes and functions, this type of testing compares UI screenshots to detect accidental visual changes after the code update. It allows developers to find and fix visual bugs to deliver a smooth user experience. It's suitable for systems with regular UI updates.
Challenges in Regression Testing
Even though it helps to improve software quality, regression testing in software testing poses several challenges for developers. With constant updates and new features, it's hard for developers to re-check codes repeatedly to ensure the software's seamless performance. Regression testing brings many other challenges for the developers, such as:-
- Lengthy Process:- Running a full regression test is tedious and requires a lot of time, especially for large and complex projects. This process becomes even more lengthy and draining as new features and updates are added to the app. All this causes drawbacks like prolonged development time and increased resource costs.
- Prioritizing Tests:- Running test cases for every code after each update is impractical. And this is where test prioritization becomes useful. Developers study code updates and predict their impact on the software. It helps to prioritize the tests that are most prone to regression. However, wrong prioritization risks missing regressions and bugs.
- False Positives or Negatives:- Regression tests can sometimes produce false or inaccurate results. For instance, a false positive occurs when the test flags a problem that doesn't exist. Similarly, a false negative occurs when a bug or issue goes unnoticed, possibly because the test is flawed, wasting valuable time.;
- Finding the Problem:- When a previously working feature is broken during the test, it's hard to find the specific code update that caused this issue. And since the codes are interconnected, changing codes in one part can affect the other parts of the system. And the process of finding and fixing such issues is very complex and tedious.
- Managing Test Data: Regression testing in software testing needs specific data to work. Managing this data is tough, especially when the software grows. Updating this data is vital, as not doing so can lead to incorrect test results. This data can become excessive, and creating new data takes time. Effective data management is crucial for reliable regression testing.
- Teamwork:- Successful regression testing relies on clear communication and teamwork among the developers, testers, and stakeholders. Not doing so can cause issues like unclear needs, poor communication for system updates, and priority testing disputes. All this results in prolonged development time and residual bugs in the software.
- Automation Issues:- While automation aids in regression testing, it's not always easy. Automating complex test cases, especially those with user interfaces, is technically challenging. Maintaining automated test scripts becomes more arduous as the software evolves. Successful automation relies on careful planning and execution.
Best Visual Regression Testing Tools
Creating a seamless user experience needs a closer look at visual details. Visual regression testing tools are crucial to ensure UI stability. Such tools automate screenshot comparison that pinpoints even minor changes, which allows developers to handle UI issues effectively. Below are the prominent visual regression testing tools to look for in 2025.
- Appsierra
Best for large-scale, AI-powered visual regression testing Appsierra AI-driven visual regression testing helps teams and firms ensure accurate system UI across all platforms. It automates UI error detection across different browsers, devices, and screen resolutions while linking it with CI/CD which helps in real-time reporting and quick debugging. It helps organizations deliver quality products and experiences to customers.
- Percy by Brownstack
Best for CI/CD pipeline integration for automated visual testing Percy automates visual testing by capturing and comparing UI screenshots, which helps to identify visual errors and changes quickly. It blends with CI/CD pipelines and supports responsive visual testing across different screen sizes. It provides features like snapshot stabilization that help to reduce false positives by carefully handling the UI animations.
- BackstopJS
Best for open-source users looking for a flexible, self-hosted solution BackstopJS is an open-source tool that helps to automate visual regression testing for web applications. It captures the snapshot of web pages, compares it with reference images, and creates detailed reports to highlight any visual change. It's highly customizable, which allows users to create custom test cases. Plus, it will enable a seamless connection with different workflows.
- LambdaTest
Best for large-scale and OS testing across browsers. LambdaTest offers an innovative visual testing feature that helps teams quickly compare screenshots and find visual bugs and errors. By uploading comparison screenshots, testers can now see visual problems with ease. Its AI-powered image-comparison engine helps to refine accuracy and provides access to over 3,000 browsers and operating systems for complete testing.
- SikuliX
Best for automated GUI testing with image recognition SikuliX is an open-source visual testing tool that uses image recognition to automate GUI interactions. It can quickly examine and interact with the on-screen elements, making it suitable for systems with limited source code access. It supports automated visual testing across several platforms, including website pages, desktop software, and mobile applications.
Cost of Regression Testing
The cost of regression testing in software testing includes direct and indirect charges. Direct cost covers the tester's salary, testing tools, and the training process. Indirect cost, while obscure, can notably increase the cost of regression testing. It includes time spent by the team fixing bugs, possible delays due to missed regression and opportunity costs due to skipping tests can lead to even greater expenses in the future.;
Therefore, it's advised to first invest in a good testing strategy as it will help save money later on by avoiding such problems. Furthermore, regression testing can vary based on project size, complexity, and the testing method chosen, but typically costs about 15-25% of the development cost for small or more manageable projects and can cost as high as 30-40% of the development cost in case or more significant or more complex projects.
Regression Testing Strategy for Large Projects
Regression testing in software testing requires a solid strategy in the case of large-scale projects. Their size, complexity, and regular updates make them prone to unexpected issues from minor changes. A clear testing strategy helps to avoid new or recurring defects and allows developers to reduce development costs and deliver a reliable product to customers.
- Define Goals:- The first step is to define clear goals and scope for your project. It includes highlighting the software's most crucial functions and task flows, as these areas should be the main focus of testing. Since every test case is different, risk-based prioritization is vital. It allows the team to focus on the bug-prone areas carefully.
- Test Case Management:- It's necessary to have a complete test suite to make regression testing effective. This suite must cover all functions and task flows as stated above. Updating test cases frequently is essential, as outdated test cases are futile and can result in false results. Efficient test case management ensures accurate test results.
- Automation Plan:- Automation is the key to making your regression testing effective, especially in large projects. Automate regular tasks to reduce testing time and free up valuable resources. Choosing the correct tool for test automation is crucial as it results in a seamless connection with the existing development setup and CI/CD pipeline.
- CI/CD Integration:- Integrating regression testing into the CI/CD pipeline is helpful as it allows automated testing with every new build and provides instant feedback on regressions. Setting utilized triggers for specific regression tests based on change type or release stage eases the testing and ensures relevant test execution at each stage.
- Environment Handling:- Dedicated test environments are essential for accurate and reliable regression testing. Such environments help prevent disturbance and ensure the tests run under realistic conditions. Maintaining such environments is crucial as a stable test environment helps assure reliable test results.
- Data Reporting and Analysis:- Clear regression test reports are crucial to communicate results and highlighting concerns. Similarly, analyzing test results is equally important as it helps gain valuable insights by highlighting trends, patterns, and problem areas. Likewise, strong bug tracking allows for effective logging, tracking, and fixing.
- Version Control:- Like the source code, the test scripts, test data, and other test assets should also be managed under version control. It helps ensure that everyone uses the correct versions of test assets and improves collaboration between teammates. It also makes it easier to track changes made to the testing process.
Conclusion
Regression testing in software testing is an essential step that helps to improve software quality and performance. This blog explored the different aspects of regression testing like its importance, types, and meaning. We also discussed how visual testing tools and version control can help boost the accuracy and effectiveness of regression testing. A precise strategy is crucial for promising software development and helps ensure its reliability and stability.
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