With the advent of the CI/CD process, changes are inevitable and continuous. Any changes made to the software applications can produce an unexpected outcome and can impact businesses at large.
In this article, we discuss:
■ What is Regression Testing?
■ Examples Of Regression Testing
■ Why is regression testing important in Agile and CI/CD?
■ When Can We Perform Regression Testing
■ Five Types of Regression Testing in CI/CD
■ Why automate Regression Testing?
■ Common approach taken to Automate Regression Testing
■ Challenges with Regression Test Automation: Must know for the QA Engineer
■ How to automate Regression Testing by applying AI/ML
Regression Testing is a type of Software Testing used to verify the changes made in an application that does not affect the existing functionality. After the bugs are identified by engineers (software testers or developers), the developers modify the source code to make it bug-free. If this process is completed every day, then it is often known as Continuous Testing. You can refer to the following diagram:
What is Regression Testing?
Regression Testing is carried out to ensure that the changes made do not introduce any anomaly or cause components to fail. Here, the test cases covering the modified and affected parts of the code are selected and executed. However, these test cases are selected and executed manually by QA testers, which can be time-consuming and frustrating.
Let’s discuss an example of Regression Testing.
A testing team performs the manual regression testing at the end of each iteration. Regression testing by this team completely relies on test cases written during the development phase. Maintenance of the test suite is done manually by the team to delete and fix inefficient test cases, which help to maintain the test suite. The testing reveals issues with particular features that get changed often. Development teams identified the defects, rectified them, and made the feature stable.
In this blog, we shall discuss the best way to automate the Regression Testing process in CI/CD.
Examples Of Regression Testing
Regression testing is an essential practice in software testing. It can be based on attributes like visual, functional, performance, and security, as well as application types such as web, mobile, API, and desktop. These tests can also be for the application layer (UI and API) and are performed end-to-end.
To perform regression testing regularly on existing code, testers write and build automated test suites. They also filter out release-specific tests to re-run on affected areas from new releases.
To understand this better, let’s consider an instance. Suppose there’s an existing community-type mobile application where users can share their insights on different issues in the form of posts, other users can read and comment on these posts. If a new feature is added for ‘Recommended Posts,’ regression testing is done to make sure that the new functionality does not negatively impact the app’s existing features. This testing may involve running manual or automated tests to check the basic functionality and identify any bugs in the newly updated version. If any bugs are found, they are immediately fixed, and the regression tests are repeated until all tests come out clear.
Another example can be a video editing application. Once the application has been built, its fundamental features are tested to ensure they work fine. The app may be tested with some 100 use cases, and the application is released to the market when the tests all pass.
After a few months of the product performing well in the market, you realize it’s the right time to iterate the app and introduce a new feature. The new feature can be, say, an audio mixer. After the new feature is incorporated, you will need to run regression tests for the new feature in addition to re-running tests for the core features. While testing the new feature with new use cases will help check the performance of the newly added audio mixer, retesting core features will help ascertain if any bugs occurred in the app’s basic functionality.
Regression testing helps catch any issues in fundamental code changes and address them in a timely manner. It is most valuable for companies that release digital products and need to regularly perform regression testing to ensure the core features of these digital products are working well.
Why is regression testing important in Agile and CI/CD?
Apart from the basic requirement to verify that a new code does not cause issues in the core features of a software application and hamper its overall performance, regression testing offers other benefits, such as checking the outputs for many commands. Regression testing aids in assessing the quality of output and making modifications if required. For example, if a video editing tool includes a compiler, the time it takes to compile (compilation time) can be an important indicator for reviewing and analyzing regression test results.
So, sometimes, making a slight change in existing code can significantly impact how a product works, and it can be difficult to undo those changes. However, with regression testing, a software developer/tester can continuously test new code and make improvements. If your company
releases updates frequently, creating a faster and more efficient feedback loop to find and fix any problems before production is necessary.
CI/CD is a series of automated continuous integration and continuous delivery/deployment tests that help software developers rigorously test and integrate new code. These tests are crucial as they allow for continuous testing while changes to the existing code are made to bring out a better product and improve the end-user experience.
Regression testing extends beyond making sure everything works correctly to fix visual bugs caused by changes in the codebase. This type of regression testing is called “visual regression testing,” and it helps detect visual problems that might occur when changes to the code are made. For instance, if something in the code is changed, it might cause some buttons to malfunction (non-clickable buttons) or some images to appear misaligned.
Instead of conducting tests individually to check every single device manually, automated regression tests can detect bugs for several devices simultaneously and alert developers to ensure they can address the problems in time.
When Can We Perform Regression Testing
Regression testing is performed whenever changes are made to a system and the code is modified. This includes introducing new features, fixing bugs, improving performance, and making changes to platform specifications.
For example, if a website has a login functionality that only allows users to log in using email, a new feature can be added to allow login via Facebook. To check email login still works, regression testing should be done.
Regression testing also helps incorporate a requirement change. For example, if the ‘Remember password’ functionality is removed from the login page, regression testing should be done.
Regression testing is also necessary when defects in the codebase or patches are fixed. For instance, if a tester reports a broken login button and it is fixed by the developers, regression testing should be done to ensure the button works properly while also testing other related functionalities.
Regression testing is also needed when performance issues are fixed. For instance, if a slow-loading page that would take, say, 5 seconds to load is fixed, regression testing should be done to ensure the loading time has reduced and the fix hasn’t impacted other features on the page.
If any enhancements in platform specifications are made, even if the code is not changed, regression tests should be performed to ensure new specifications haven’t impacted the app’s function. For instance, when the platform changes from Android 10 to Android 11, regression testing can help ensure the application functions correctly on the new platform.
Regression testing also helps meet project-based requirements. It can help determine the output of a modification at an early stage, such as decoding the compilation time.
In addition to these scenarios, regression testing is also applied when a new software version is released, changes to the UI are made, and a third-party system is integrated with the existing system
Five Types of Regression Testing in CI/CD
CI/CD allows organizations to deliver software quickly and efficiently. CI/CD facilitates an effective process for getting products to market faster than ever before, continuously delivering code into production and ensuring bug fixes via the most efficient delivery method. Regression testing in a CI/CD pipeline can be used to make releases lean, efficient, and intelligent because it helps reduce the test execution time, cost, and resources and, at the same time, enhances the software quality.
There are five different techniques of Regression Testing based on the nature of changes made in the software or bugs repaired (or reversely the intention of the testing). They are as follows:
1. SELECTIVE REGRESSION TESTING
As the name suggests, this type of regression testing involves the execution of only selected test cases from the test suite when there is a change in the code. There is no need to run the complete test. Some of the benefits of Selective Regression Testing are:
● Faster to test and check the outcome of the code
● Compare the effect of both previous code and changed code
2. PARTIAL REGRESSION TESTING
This type of regression testing involves the selection of certain related parts that could have been affected by any recent changes in the code. Partial Regression Testing involves adding new parameters to the existing system to determine if the system is working as usual after making modifications. Some of the benefits of Partial Regression testing are:
● Easy to detect critical bugs in the current code
● Quick to perform and less time-consuming
3. COMPLETE REGRESSION TESTING
Complete regression testing involves the examination of the entire application. It is used when QA teams want to perform a 100% coverage of test cases. This regression testing is usually used in cases where the project owner doesn’t want to make big or more changes during the testing. Some of the benefits of Complete Regression testing are:
● 100% coverage of test scenarios and test cases
● Zero bugs get introduced in the application
4. PROGRESSIVE REGRESSION TESTING
Progressive regression testing comes into the picture when any project requirements are changed or any new build is deployed. The new test scenarios are created based on the needs. Testers can execute the newly added test scenarios without touching the current application features.
● The benefits of Progressive Regression testing are:
● Focused on a newly developed app or feature
● Reduced cost and time to test
5. CORRECTIVE REGRESSION TESTING
Corrective regression testing is done when existing test cases are used to rapidly check for a tool and find out if there are some abnormalities. This regression testing is conducted on current test cases that involve no code changes. The benefits of Corrective Regression testing are:
● Rapid check to ensure the application is working well from a critical functionality stand-point
● Can be carried out repeatedly
Why automate Regression Testing?
1. Enhanced Productivity
One of the biggest benefits of Regression test automation is that it reduces the dependency on testers and, hence, frees up resources.
2. Better Stability and higher throughput
Regression test automation helps reduce the overall cost of testing by providing quick executions with minimum use of resources.
It is important for Regression test automation tools to provide self-healing for automated tests generated, thus helping the tests to dynamically adapt to the changes in the code during the development process. This brings an overall reduction in code defects, thereby providing stability to the product and improving efficiency.
3. Quick to Test and Execute
Regression test automation ensures that tests are run 24/7, 365 days a week. With a test scheduler, one can do things like setting up test execution during the night, so no one has to sit around and wait for test results or execute them at specific time intervals.
4. Quick Defect Resolution
Regression test automation, when done in Agile way of delivery, often provides feedback after every execution, thereby ensuring that defects are regularly rectified or taken care of and the piece of software is defect-free before going to production.
Common approach taken to Automate Regression Testing
CI/CD Architects often want to automate the software delivery process to ensure the software is delivered at speed. Testing is a function that is sought after by many architects for automation. Let us understand the stages of Regression Testing in which a QA engineer would perform Regression Testing and the various tools available for its automation.
Typically, there are three stages of Regression Testing:
1. Test-suite generation stage
Here, a QA engineer would generate the test suites (including the test cases and script) based on the code changes made in the application and the time in hand for testing. It can range from hours to days based on the complexity of changes in the applications.
Tools to automate Regression Test generation: Selenium, Appium, and Cucumber help in generating automated test-suites.
2. Test-suite execution stage
After these test suites are generated, QA engineers or software testers can perform Regression Testing by executing the test case based on their requirements. The test-suite execution can be scheduled or made to run as per the requirement, easily using an automation platform. Continuous integration tools are often handy as they usually demand very little interference from software testers to find the impact of the new applications and to identify any new bugs.
Tools to automate test-suite execution: Jenkins
3. Test-suite maintenance stage
After the developers make new changes to the source code, Regression Tests also need to be changed. Maintaining the test cases becomes a highly complex process that requires substantial human effort when done manually. Many tools provide self-healing for automated tests generated, thus helping the tests to dynamically adapt to the changes.
Tools to maintain test-suite execution: Healenium
Refer to the below example, which depicts an idea of the tools used to automate certain stages in the Regression automation cycle:
Challenges with Regression Test Automation: Must know for the QA Engineer
There are particular challenges in architecting Regression Testing automation in a CI/CD process using incumbent tools.
Automation of all three stages of Regression Testing, that is, test suite generation, test suite execution, and test maintenance, can prove to be a big hassle. It includes taking 2-3 tools and involving testers to write scripts to maintain and integrate the tools for automation. Tools may execute, however, QA engineers still must spend time identifying test cases based on the impact. In the CI/CD proc
changes are happening every day and are planned to be deployed fast, selecting the right test cases to minimize failure is time-consuming.
Maintaining the test cases while adapting to the changes is the biggest challenge in today’s software testing world. Huge test case repositories are created, which are still maintained by QA engineers manually.
How to automate Regression Testing by applying AI/ML
If there is a scope of automation one should definitely move ahead with the automation. Manual processes are slow, time-consuming, and tedious. Besides, they are error-prone. Testing is a very important part of delivering software in a fast and reliable way. So organizations must find the right tool that will fit with their toolchain and will not be a bottleneck while you scale.
The best part is that all these challenges can be overcome by applying AI to Regression Testing. We have come up with ignio AI.Assurance – an autonomous assurance product that enables enterprises to deliver better software faster without any hassle. ignio AI.Assurance can find the business impact of any code change, formulate test suites automatically, and provide the flexibility of choosing a testing strategy, executing it, and getting success/failure reports in the dashboard.
The QA engineers of Fortune 500 companies trust us to automate all the stages of Regression Testing so that they can focus on other strategic tasks associated with DevOps, which they were unable to do earlier due to the frustrating testing approaches. Now, they can spend more time with their families, eating pizza and getting a good night’s sleep.
