A Comprehensive Tutorial on Regression Testing

A hassle-free, fully working application is difficult to create and release. Before the final deployment, it must undergo many sorts of testing. App or web testing helps to uncover faults and gaps that are in conflict with the actual requirements while ensuring that the product is functioning as intended or designed.

Regression testing will be our whole emphasis in this article.

This post will serve as a comprehensive how-to for learning regression testing concepts at the novice level. Everything will be covered, including what regression testing is, its advantages, why it is necessary, how to conduct this testing, and much more.

Therefore, let's begin.

What is Regression Testing?

Regression testing is a testing method used to ensure that an application's present functionality is not affected when its code is modified, enhanced, or updated. That entails rerunning any previously run test cases that are affected by the code modifications.

Regression testing is mostly used by testers to confirm that after a bug is fixed, the newly added functionalities have not caused any issues or introduced any flaws in the application's prior working version. It is to make sure the programme update or modification isn't harming the current feature.

Regression tests need to be run as frequently as feasible and should be a part of the application development life cycle. It is the last step because it validates all of the application behaviours.

Regression testing is responsible for the general stability and functionality of an application's existing features. Code changes could introduce dependencies, flaws, or malfunctions. Regression testing aims to eliminate these risks so that the previously written and tested code is still viable and functional in the face of ongoing changes after each update. Regression defects are when an application stops functioning properly after a change.

Test cases are run as part of every application testing process to evaluate performance. Reruns of test cases are used in regression testing as well to evaluate how well the programme performs with earlier functionality. The new modifications shouldn't produce any bugs either.

Why Is Regression Testing Necessary?

There are two main purposes for regression testing. First, if improvements are made to correct a flaw or defect, they fail. Additionally, whenever an issue is fixed or introduced.

When programmers add new code or new features to the application, regression testing is required. and the application is altered by new improvements like increased security, performance, or functionality as well as through updates, bug patches, and feature modifications.

Both recently introduced and current features are dependent on a number of other features. So that the unmodified code is not impacted, it is imperative to verify that the new code complies to the older ones. It is also important to be aware that when one defect is addressed, several new ones might appear.

Regression testing is essential since any changes to the application's source code require verification. The teams checked that the modified application component worked as intended during this testing and that the modification had not negatively impacted any other parts of the programme.

Regression Test Types

Regression testing that is conducted on individual units is known as unit regression testing. The QA engineers analyse the code in this case as units and ensure that all dependencies that arise from the units are blocked out during testing. so that the unit can be independently checked without a problem.

Testing for partial regression is carried out to ensure that the code continues to function properly after modifications. The actual or unaltered code is then combined with the tested components.

Complete Regression: Complete Regression is used when there is uncertainty regarding the influence of a code modification on other modules after it has been applied to a number of modules. Here, the entire programme is checked to look for any modifications brought on by the code update.

Progressive Regression Testing: This method of testing works best when the programme has undergone just modest code modifications. Testers can now verify that the modified code does not impact any of the earlier functionalities.

Corrective Regression Testing: This testing ensures that all functionality operates as intended even when no new code modifications are performed. These test cases can be reused by testers throughout the whole development cycle.

Advantages Of Regression Testing

One of the most popular methods for testing applications is regression testing. The testing team can profit from its advantages throughout development cycles if it is applied properly. Here are a few of its advantages.

• Regression testing finds flaws introduced by fresh code alterations or additions that cause the problem. This promotes raising the calibre of applications.
• As much regression testing as possible should be automated in order to improve testing, increase accuracy, and speed up issue detection.
• When new functional components are added to the programme, integration testing and regression testing are compatible.
• Integration testing verifies that no flaws are introduced and that all of the capabilities of the application operate as intended.
• Regression testing ensures that issues and outcomes that have already been fixed won't recur.
• ensures that any application code changes do not affect previously tested code.
• The users receive an application with the fewest possible flaws and issues thanks to regression testing.
• The users receive an application with the fewest possible flaws and issues thanks to regression testing.

Regression testing challenges:

Regression testing provides many advantages, but there are also a number of difficulties that a tester may run across. Regression testing has a number of difficulties, including:

• A tiny modification in the code may cause problems with the present functionality, so this testing must be done even for such changes.
• Executing successive regression tests will be a laborious and time-consuming operation if automation is not used in regression testing.
• Test suites grow reasonably large as regression tests are repeated often. Regression testing cannot be completed in its entirety due to time and financial constraints.
• Another difficulty is determining the frequency of regression testing to correct bugs with each modification or upgrade.
• It is quite difficult to maximise test coverage while decreasing the test suit.

Regression Testing Test Case Selection

A crucial stage in regression testing is choosing test scenarios. Test cases assist the testers in figuring out how to fix faults that have arisen as a result of changes in the code and retain the functioning of the particular application during testing.

The major pointers you can use while choosing test scenarios are shown below.

1. Concentrate on test cases that have undergone recent revisions or changes.
2. Concentrating on certain test scenarios may increase the likelihood of discovering problems.
3. Test the quality and complexity of the application by concentrating on complicated test scenarios.
4. Pick the application components that crash most frequently or have the highest defect suspicion. Therefore, you can select test situations where there is a larger likelihood that faults or defects will occur.
5. Choose test cases that cover the modified modules.
6. Select test cases that cover the essential features or functionality of the programme.
7. Select the appropriate test cases that are effective with the target applications, satisfy organisational objectives, and address client demands.

How to do Regression Testing

Now that practically every aspect of regression testing has been covered, it's time to learn how to conduct the testing.

Depending on the test cases, regression testing can be done manually or automatically. The scope of regression grows when programmes are loaded with more and more features, however manual methods are typically time-consuming. Thus, this testing is frequently automated to maximise efficiency and reduce associated expenses.

In automated testing, quality assurance testers create test code for the script and run these test cases using regression testing tools. Test cases with repetitive actions are better suited for automated testing because performing them manually can increase the risk of human mistake.

However, as exploratory tests are not supported by automated testing, manual testing is preferable to use when the user interface changes. Additionally, human regression testing is an option when test cases change regularly, but automated testing is the ideal option when test cases are fixed.

Here are some crucial actions that must be taken in order to complete regression testing properly.

The first step is creating a test suite while taking into account the criteria specified for choosing test cases for regression testing. The test suite's test cases will then all be automated, and the regression suite will be updated as needed. 

This could involve finding fresh flaws in the test case, so they are not overlooked any more. Executing the regression test cases after each time a change is made to the code, a bug is addressed, a new feature is created, or the functionality of an existing feature is improved. 

Finally, make a test status report that indicates if the execution of the test cases was successful or unsuccessful.

Techniques for Regression Testing

Enhancements, bug fixes, optimization, and adjustment of current features are all part of application maintenance. The application can stop functioning properly when changes are made to correct faults. Regression testing is therefore crucial to perform. Regression testing can be done in a number of ways. They are listed below.

Retest All

With this method, all of the test cases in the test suite are run again to make sure all bugs are found and fixed. Compared to other procedures, this one demands more time and resources.

Regression Test Selection

Due to the fact that only a subset of the test suite's test cases are rerun and not the complete suite, this approach saves time, effort, and resources. The decision is made based on the code that has been modified and whether or not the application is impacted by the modification.

According to this strategy, test cases are ranked from medium priority to low priority based on their impact on the application, criticality, failure rate, and frequently used feature. The higher Priority items are carried out first. The number of regression tests will undoubtedly decrease with priority-based test case selection.

Hybrid

This method combines the test selection and test case prioritization techniques. It is usually preferable to only work on the test cases that are re-executed according to priority rather than working on the whole test suite.

Selecting the Proper Testing Tool for Regression

Selecting the appropriate automation tool is essential for executing regression testing smoothly and effectively. It is a challenging effort to add and update the Regression test. Because applications change regularly, automated Regression test cases typically need to be updated frequently.

Checking whether the tool makes it simple to add or change test cases is a need when choosing an automation testing tool for regression tests.

It is advised to think about LambdaTest while you weigh your alternatives among the various solutions on the market. It is a cross-browser test automation tool that runs in the cloud and consolidates all testing on a single platform. It enables the team to get rid of regressions and make sure the applications continue to function exactly as they did prior to making any changes.

For both manual and automated testing of your website, online services, and mobile application, LambdaTest offers an all-in-one test solution. Your regression tests can be automated here quickly and efficiently. Numerous programming languages, including Java, Python, Ruby, C#, and Javascript, are supported by this platform.

With combination versions, it offers more than 3000 actual devices, browsers, and operating systems. For testing websites and mobile applications, LambdaTest provides a safe and dependable platform. 

It provides a collection of tools for automating web applications. It conducts high scale parallel tests with automated builds, integrates well with various defect tracking tools. 

It also automatically schedules tests without user iExcellent browser interaction features, the ability to design flexible, maintainable automated regression tests, flexible defect reporting with video results capture, running multiple scenarios simultaneously with the Smart Scheduling, Execution are just a few of the additional features it offers.