In software development, even a single line of new code can sometimes cause unexpected changes to the existing functionality. Applications are becoming more complex, and development speeds are increasing, which makes it even more important to test recent code changes to ensure they haven’t unintentionally broken existing functionality. Regression testing is very useful in this situation.
To ensure that new design modifications do not negatively impact the software’s current functionalities, regression testing is done. It is a kind of risk mitigation to keep software stable and bug-free and to confidently release software enhancements within the Agile and DevOps environments at a very fast speed.
In this blog, we are going to discuss in detail what regression testing is and why it holds a lot of significance and how it could be done in an efficient and scalable manner.
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What is Regression Testing?
Regression testing is the re-execution of some test cases that were executed previously to check that the existing functionality of the software is not broken due to some recent changes made in the code base. Changes could be:
- Bug fixes
- Code enhancements
- New features
- Configuration changes
- System upgrades
The Purpose of Regression Testing
The primary aim of regression testing is stability. Without this, a very minor bug fix could create new problems in other areas of the application that could potentially lead to errors.
Let’s have a look at a few important functions it serves:
Preventing Backward Bugs
Regression occurs when a feature that was previously functional abruptly stops functioning due to new code modifications. Regression testing stops these sorts of regressions by ensuring that existing functions don’t get broken.
Reducing User Impact
Bugs that make it into production will damage your brand and, more importantly, user trust. Regression testing catches bugs early in the development pipeline, reducing the likelihood of user-facing failures.
Supporting Agile and CI/CD
Modern development cycles are short and iterative, and regression testing gives the safety net needed to release software quickly and often without compromising on quality.
When is Regression Testing Needed?
One thing to remember is that regression testing is an ongoing effort rather than a one-time process. Some common triggers for regression testing include:
- Code merges: When new code is incorporated into the existing code.
- Bug Fixes: Even minor bug fixes can introduce unintended changes to unrelated functionality.
- Feature Updates: Adding new features may have an impact on existing features.
- Configuration or Environment Changes: Changes to the database, servers, and libraries may impact the behavior of the application.
Manual vs. Automated Regression Testing
There is a need for both manual and automated regression testing in the QA process since each has different purposes and has different pros and cons.
Manual Regression Testing
It is a time-consuming process since testers must manually carry out the test cases. It’s ideal for:
- Small applications
- UI/UX validation
- Complex user interactions
- Exploratory testing
Automated Regression Testing
Automated testing relies on scripts or other technologies capable of running regression tests. It’s ideal for:
- Large, complex applications
- Repetitive and frequent testing
- Continuous integration environments
For projects with longer build cycles and regular releases, automation is the way to go. It’s faster and much more suited for scale.
Developing a Regression Test Suite
A regression test suite is the cornerstone of every regression testing approach. Test cases that cover every important aspect of the program should be included in the suite.
Key Considerations:
Test Case Selection
Choose test cases that are more prone to regression from recent changes. Consider:
- High-risk areas
- Key business functionality
- Functionality with previous defects
Test Case Maintenance
Over time, some tests may become obsolete, rarely executed, or unintentionally duplicated. Periodically review the suite to ensure it is lean, efficient, and relevant.
Test Coverage
Aim for comprehensive coverage but avoid redundancy. Each test should validate a specific functionality or scenario.
Realistic Test Data
Using real-world data makes regression tests more meaningful and, more importantly, increases the chance of finding subtle bugs.
Challenges of Regression Testing
As with any process, regression testing has issues. Being aware of them will allow you to create better solutions.
Time Consumption
Running a full regression suite can take hours (depending on the size of the application), so it’s wise to determine which tests are critical and automate them.
Test Suite Bloat
As your application grows, so does your test suite, and with continuous growth you might end up testing a lot more than you need to or, even worse, have a lot of unnecessary maintenance for tests that are not important. It is good practice to periodically clean your test suite.
False Positives/Negatives
Poorly written test scripts can give you incorrect results. This error can waste time and resources and reduce confidence in production.
Regression Testing in Agile and DevOps
Agile and DevOps are about speed. Code is written, tested and deployed quickly, sometimes even daily, which makes flexible and efficient regression testing essential
In Agile
Agile emphasizes providing working software through rapid development iterations, and each iteration brings some change. Regression testing is critical for ensuring stability in this situation.
- Usually, tests are run at the end of every cycle.
- Automation helps keep pace with fast development cycles
- Test cases can be continuously updated to reflect changes to user stories
In DevOps and CI/CD
In DevOps, the idea of CI and CD is key for both developing code and developing applications. This then integrates regression tests into the pipeline.
- Regression testing workflows are triggered as part of testing for every commit of code
- Since tests are automated, changes are verified immediately.
- Immediate feedback from automated regression tests provides constant risk assessment during an operation, enabling the team to roll back changes quickly if required.
Popular Regression Testing Tools
The choice of tool depends on your tech stack, application type, and team preferences. Here are some widely used options:
- Selenium: An open-source browser automation tool. Great for automating tests for web applications. It may be used in a variety of languages.
- Cypress: Cypress was developed for modern web apps. It is fast, dependable, and has debuggable testing.
- PyTest: One of the most popular Python frameworks. PyTest is powerful, easy to learn, and highly extensible. It supports fixtures and plugins and is easy to integrate into CI/CD tools.
To support seamless, reliable regression testing, especially in fast-paced Agile and CI/CD environments, leveraging robust tools is essential. LambdaTest is one such platform. LambdaTest is a GenAI-powered test execution platform that allows you to do automated regression testing in real time. It allows you to test on over 3,000 real devices, browsers and operating systems.
With LambdaTest, you can cut down on overall test time by integrating with your CI/CD pipeline and also taking full advantage of parallel test execution capabilities. LambdaTest scales per your requirements and maintains quality, in addition to providing excellent support for multiple popular frameworks, including Selenium, PyTest, and more.
The Changing Landscape: The Future of Regression Testing
The future of regression testing will be increasingly influenced by the following technology trends:
AI-Driven Testing
AI will ultimately be helpful in reducing redundant tests, prioritizing areas of highest risk, and identifying patterns to build possible test cases.
Predictive Test Selection
Machine learning models can anticipate which elements of an application are likely to fail, enabling teams to concentrate their testing efforts.
Self-Healing Scripts
Some of the new testing tools have self-healing scripts that adjust automatically if the UI slightly changes, reducing maintenance effort.
Testing as a Service (TaaS)
Cloud-based testing platforms will deliver the infrastructure, tools, and frameworks as a service. Commonly referred to as “Testing as a Service” (TaaS), this will help eliminate the need to maintain your own testing infrastructure, reducing your testing organization’s overhead.
Best Practices for Regression Testing
Rest assured, you can get the most out of your regression testing by employing these best practices:
- Automate Frequently Executed Tests: Automating tests that are commonly run can help you save time and effort as well as reduce human errors.
- Incorporate in CI/CD: Integrate with CI/CD: Ensure that regression tests are performed with each build.
- Use Version Control: Maintain a history of test changes alongside code changes.
- Use Clean Test Data: Testing with realistic, uniform data leads to more reliable testing.
- Update Test Suites Regularly: Add new cases, remove ones you will not need again, and try to improve performance.
- Review Test Results on a Regular Basis: As you review your test results, look for patterns of failure that may indicate broader concerns.
- Facilitate Collaborative Engagement: Identify multiple test strategies and collaborate with different teams and members. (developers, QA professionals, product managers, etc.)
Conclusion
In the current world of rapid development cycles, where the code frequently changes and the time for releases is shorter, regression testing cannot be seen as a luxury; rather, it is an essential. It serves as a safety net to protect existing functionality while giving confidence to the teams to deliver new features and fixes.
In Agile, DevOps environments, where change and speed are a constant, regression testing serves the important role of providing stability and structure needed to keep progress from turning into chaos.
Ultimately, regression testing’s is a way of maintaining trust. Trust in your code, trust in your process, trust in your team, and trust in the software you release. Regression testing’s is an investment that will carry over as your software grows and make every change a progression, not a regression.
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