The Ultimate Guide to Regression Testing: Strategies and Tools

Software testing has an undeniable role in the development of software products, applications, and programs. It occupies an inseparable place in the Software Development Life Cycle and prevents bugs and errors from ruining all efforts before the final delivery to the clients. A regression in the overall development of tech products introduced the concept of regression testing, which is firmly discussed in this article.

What is Regression Testing?

Regression testing is like 'serving a hot cup of tea, but tasting it prior’. You have to be sure of the non-prevalence of anything surrounding or in your recipe that could destroy the tastefulness of the tea.

Similarly, when you are going to present a software, program, or application, your final product should ensure that it is well-tested and there will not be any single problem after the bugs and errors are fixed. In short, regression testing assures that any alteration in the current code or program would not hamper its earlier functionality. It is actually executing the whole or partial subset of the test cases that have already been executed to verify that the existing functionalities are performing as they were earlier.

This kind of testing ensures that the altered program is still functioning as it was earlier. For example, an updated software program is still working following the most current revisions and code changes.

Why do we do Regression Testing?

Tech businesses strongly believe in delivering high-quality software solutions that meet business requirements and fulfill maximum user expectations. The need to serve better gives rise to the responsibility of performing better through the tools, techniques, and services provided.

As a critical method or practice of quality control and testing, regression testing helps in

• Maintaining software stability,
• Minimizes risks, and
• Ensure that the recently made changes to the codebase do not harm the existing functionalities negatively.

When to perform Regression Testing?

The answer is simple here: ‘once after the new features are added or alterations are made’.

For example, if a tester has raised an error or identified a bug in a system, it is then reported to the developer, and the developer would make relevant changes to the code to meet the requirements. After this, a set of functional and non-functional tests is conducted to confirm there are no glitches in the existing functionalities of the code and that it still resolves the purpose. So, when it is asked when to perform Regression Testing, there are several measures, like:

1. When new functionality or features are added to the software program or application.
2. When a bug or defect is fixed.
3. When an issue related to functionality or performance is fixed.
4. When an update is required for the system.
5. Due to changes in the development environment.

There is a famous quote by Lisa Crispin and Janet Gregory from the book ‘Agile Testing: A Practical Guide for Testers and Agile Teams’ shown below:

How to Perform Regression Testing?

Exceptional regression tests ensure bug fixes and software modifications are absolutely free from the new issues. Instead, they are helping the software programs or applications meet the requirements of the users. The software testers perform regression testing in the following ways and provide guidance on how to perform regression testing for the desired results:

#1. Finding Bugs: They first try finding any new bugs by identifying and debugging the existing code.

#2. Fixing The Bugs: Once the bug is identified, necessary changes are made to fix it, ensuring that the code is working correctly.

#3. Selection of Regression Test Cases: Then, relevant test cases are selected from the test suite that include both the changed code and the part of the software that might be affected due to the change.

#4. Test Execution: The selected test cases are further executed to confirm that the software still works the same, even after making changes to the code. It ensures that the fixes do not introduce any issues or regressions in the code.

What are the Types of Regression Testing?

Regression testing is an essential part of the maintenance phase of Software Development Life Cycle. This testing method, with all of its techniques, can be used at all levels of testing software products, programs, and solutions. Some of the popular techniques for regression testing are as follows:

1️⃣ Corrective Regression Testing – This method covers re-running the test cases without changing the code to make the process quicker and use the same code repeatedly. This technique is specifically used when there are no changes in product specifications or customer requests.

2️⃣ Selective Regression Testing – This is the most cost-effective method of regression testing that analyzes the impact of old and new codes on the functionality of the program or app. When a block of code has been changed and the testers aim to check the impact of the new code on the old one, selecting regression testing comes into context.

3️⃣ Retest All Regression Testing – Regression testing is more like retesting all the test cases again if only minor changes have been made to the code. Though this method is time-consuming and expensive due to the need for thorough testing on each and every change, The testing ensures that changes and modifications are free from any problems with the source code.

4️⃣ Progressive Regression Testing – This method includes new test cases and scenarios and is chosen when a new system component is introduced. This testing procedure confirms that the modifications to the source code of the system do not impact the existing components negatively.

5️⃣ Complete Regression Testing – Complete regression testing involves the testing of the overall structure. It is similar to acceptability testing, which is usually applied when there are many bugs and the developers need to overhaul the entire code.

6️⃣ Partial Regression Testing – In this method, some portions of the system are re-tested to assess the impact of the introduction of new features to the system. Generally, this kind of testing is used on unchanged portions of a module that has been updated or a new block of code has been added to an existing code.

7️⃣ Unit Regression Testing – Unit testing of regression is the most popular method, where all tests are repeated for the unit when it experiences a change. Experienced testers conduct this test at non-peak hours to ensure that the software, program, or app experiencing the unit regression testing is completely ready for deployment.

Test Cases Selection for Regression Testing

For regression testing, selecting test cases seems to be a challenging task that requires skills and expertise. Here are certain criteria that seem helpful in selecting the regression test cases:

• Test cases that come across frequent defects
• Test cases validating the core product features
• Functionalities that seem more visible to the end-users
• All the complex test cases
• All the integration-related test cases
• Test cases similar to product functionalities
• Boundary value test cases
• Both successful and failed test cases are samples.

Is Regression Testing Important in Agile and CI/CD Scenarios?

Regression Testing practices seem imperative in an agile development context and play a critical role in ensuring that the new features added and incremental changes made to the tech product or software are free from all defects or disruptions and do not hamper the existing functionality of such products or software programs. Whereas in CI/CD, the methods of regression testing are used to make lean releases intelligent and efficient. This is because it helps in reducing the execution time, cost, and resources for the test, along with enhancing the software quality at the same time.

➤ In the Context of Agile: Regression Testing practices help in maintaining the core of software quality in agile development, where continuous iteration, integration, and testing of software programs, systems, and applications is paramount. When software programs or applications go through frequent releases and rapid changes, they admit some issues that must be detected and resolved early to avoid building up of the broken code that can ruin the final product. Regression testing methodologies significantly help in this regard.

➤ In the context of CI/CD: The entire series of automated tests is conducted to evaluate the new code while continuously maintaining maximum reliability. Visual regression tests are conducted to identify the inconsistencies caused by code changes in the user interface. It is particularly important in modern software development, where software programs and applications are needed to perform seamlessly across different devices and browsers.

How to Implement or Practice Regression Testing to the Best?

There are the following best practices that should be implemented to achieve higher results using regression testing processes:

1️⃣ Acquaintance with Scope – The testing between test cases might differ as per scope, system coverage, timeframe, and objectives behind them. These perspectives should always be considered, whether you are regression testing entire suite cycles or performing segment-wise regression testing.

2️⃣ Clarification of Requirements – The effective creation of the regression testing suite always requires you to define your focus area for the users, partners, and business team. While focusing on the requirements, you should essentially confirm as to:

• What would be the frequency of executions of regression testing suites?
• What would be the ways to determine significant modifications?
• What would be the timelines for achieving a comprehensive analysis of regression?

3️⃣ Stay updated about Regression Suites – The testers should keep their regression tests fully updated due to many other forms of testing being conducted by them. In fact, they should consider both the high-value practical and non-practical cases and always manage their regression test suite based on its value and priority. They should ensure that their entire testing team remains aware of all the test cases of high importance.

4️⃣ Automation of the Right Tests – If executed, a challenging task can put the entire cycle at stake, and then it should be excluded. A test failing to be automated should seriously be sent for exclusion from the regression suite.

5️⃣ Promote the Change – Transition is a continuous process in the case of web and mobile software development. This requires the testers to keep track of essential updates, like updated features or new agile needs, etc. Software capacities are also evolving continuously. Biometric verification, location simulation, modeling network circumstances, image implantation, SIM cards, infusion of audio or speech, control over all the system configurations, and efficient communication between developers and testers, are some of the sophisticated features for which organizations should include regression testing.

6️⃣ Process Organization – CI/CD tools and various other solutions are available to help you structure as well as scale the regression testing procedures. However, always plan your tests before moving on to implement CI/CD, as a rapid development approach may sometimes lead you to waste critical resources.

7️⃣ ROI Monitoring – Monitoring ROI is essential for every business to control their operations. Record generated by the regression testing tools should always be accessible, and the crucial results of the tests running over a period should be carefully observed.

8️⃣ Grade Test Scenarios – The discrepancies between the tests and workflows executed on different platforms should be essentially evaluated and recorded. In fact, the test grading technique should be implemented to ensure optimal prioritization.

How Regression Testing is Related to Configuration Management?

In agile environments, code modification is a continuous practice. Hence, a configuration management approach should be sincerely adopted when performing regression tests in agile environments. To ensure the effective performance of such tests in an agile environment, here are the guidelines to be followed:

• The tested code must be managed using a configuration management tool to ensure proper version control, and it also helps in maintaining a record of changes made to the code.
• No changes should be made to the code during the regression test phase in order to maintain the integrity of the tests.
• The database used for regression testing should be isolated to ensure consistent and reliable test results.

What are the Advantages of Regression Testing?

There are several advantages to regression testing in software, apps, and web development. Some of them are listed below:

1. The ability to test regressions happened to the product due to new changes made.
2. Improves the overall quality and stability of the software applications.
3. Makes sure there is no harm to the existing functionalities due to new code changes or bug fixes.
4. Improves customer satisfaction.
5. Ensures the non-occurrence of the previously fixed issues.
6. Lower the possibility of the risks of software failure or poor user experience.
7. Accelerated testing process and faster achievement of results than manual testing.

How Challenging Regression Testing is for the Testers?

The test suites grow in size with the progress of regression testing. However, time and budget remain limited sometimes. Thus, this makes it difficult to execute the entire test suite perfectly.

Every modification in the test case, building updates, or bug fixing brings up a challenging situation and needs careful planning if you have to determine the frequency of regression tests every time.

Testers sometimes also need to deal with a critical situation and maintain a balance when they have to minimize the test suites and maximize the test coverage at the same time.
On the whole, the regression testing can surely be challenging in terms of:

• High Upfront Cost
• Enormous Scope
• Complexity
• Testing Approach
• Time-Consuming Process

What are the Regression Testing Tools?

The market is full of a variety of regression testing tools, and each of them has its own set of functions and capabilities. Here follows a list of some of the widely used regression testing tools in the industry.

1️⃣ Testsigma – A powerful, cloud-based, and AI-driven test automation tool Testsigma is a one-stop solution to perform regression tests on your desktop, web, mobile applications, and APIs at the same time. Testsigma supports both code-based and codeless test automation and is a perfect tool for both technical and non-technical users. It can execute regression tests on different browsers and platforms and supports over 3000+ real devices and tablets and 1000+ browser and OS combos. The pro and cloud versions of this tool can be availed of with a 21-day free trial plan and a 24/7 extended customer support facility.

2️⃣ Selenium – Selenium is a globally used open-source automation test framework that functions on different web browsers like Chrome, Firefox, Safari, Edge, and Internet Explorer and permits you to create test scripts in different programming languages like PHP, Perl, Ruby, Python, and C#. The tool supports different platforms, like Windows, Mac, and Linux, and allows parallel test execution. Selenium is a powerful tool for web-based regression testing and can be integrated efficiently with TestNG, JUnit, or NUnit test frameworks.

3️⃣ Katalon Studio – Another powerful test automation tool, Katalon Studio can also be used for regression testing. Katalon supports programming languages like Groovy and Java and offers integrations with a variety of applications like Jenkins, Git, and JIRA. Katalon easily integrates into the CI/CD pipeline and supports various browsers, platforms, and devices. It uses an interesting feature called record-and-playback for recording user actions as test cases.

4️⃣ Apache JMeter – Apache JMeter is another open-source automated regression testing tool that is mainly used for load testing, stress testing, performance testing, and functional testing of web applications. This tool is entirely written in the Java programming language and supports different programs like Windows, Mac, and Linux.

Other popular tools used in Regression Testing are:

• Watir
• IBM Rational Functional Tester
• AdventNet QEngine
• Subject7
• TimeShiftX
• Cerberus Testing

How Retesting relates to Regression Testing?

Two different testing activities, i.e., retesting and regression testing, serve different purposes in the process of software testing. The detailed comparison between the two is as follows:

#1: Definition

Re-testing is executing the test cases that have failed in the previous cycles of tests to confirm if the issues are resolved or not.

Regression testing is the re-execution of the selected test cases to confirm that the software still works correctly even after the new changes have been made.

#2: Type

Retesting is a planned test.

Regression testing is a generic test.

#3: Purpose and Scope

Retesting focuses on executing defect-fixing and failure-related test cases.

Regression testing ensures that the software works perfectly, retaining all of its existing functionalities that have not been impacted by the changes made. It focuses on executing the test cases related to the new areas of the software.

#4: Test Cases Selection

Re-tests are executed only for the failed test cases taken from the previous test cycle.

The subsets of the test cases impacting the areas of the software that have been modified or changed are selected in regression testing.

#5: Test Type

The retesting process uses the same environment as in the previous testing.

Regression testing uses an environment that is similar to the production environment, including configurations related to software, hardware, and different networks.

#6: Test Data

Retesting may require specific test data relative to the previously failed test cases.

Regression testing may require a variety of test data to cover different scenarios, along with ensuring adequate coverage of the functionalities impacted by the changes made.

#7: Bug Detection

Retesting makes sure that the original fault in the software or app is corrected.

Regression testing checks for unexpected side effects while testing.

#8: Time Duration

Retesting is not a very time-consuming process, as it tests only those test cases that are related to bug fixing.

Regression testing is a time-consuming process that considers testing the overall functionality of the software.

#9: Order of Test Execution

In retesting, the failed test cases are given priority and are executed first.

In regression testing, the test cases related to the impacted or changed areas are given priority, and then other relevant test cases are checked.

Conclusion

If you wish to present reliable and high-quality products to your loyal customers, you should always opt for regression testing practices. Considering this fact, the overall information provided through this article works in the best interests of the users, testers, developers, and project owners and provides deep knowledge about the classes, techniques, and methodologies of regression testing.

However, if you still need some more guidance on this topic, connect with us immediately at Maneksoft. Our experts will always be delighted to assist you with your testing project and improve your developmental experience. 

Frequently Asked Questions or FAQs

Q.1. What is regression testing in agile?

A.1. Agile promises the continuous delivery of a stable and high-quality software product, which is the same as that promised by regression testing. The combination of both maintains the integrity and dependability of the software by evaluating the new code against its existing performance.

Q.2. Is regression testing functional in nature?

A.2. Yes! Regression testing is part of functional testing as it helps in detecting changes in the core product functionalities after any bug fixing or code-changing activities conducted on the software.

Q.3. What is the relationship between regression testing and UAT?

A.3. Regression testing helps in checking if there have been any new errors in the system due to bugs fixed earlier. Whereas, UAT checks the user friendliness and acceptance of the system. Regression testing is performed by the professional testing team, whereas UAT is executed by the clients.