Regression Testing Guide | Why Is Automated Regression Testing A Must?

In this article we will learn what is regression testing, what is automated regression testing and the following.

What is Regression Testing with example?

Regression testing is a type of software testing that seeks to identify bugs or errors in software code that was previously working correctly.

This testing is typically performed after new code has been added or modified, in order to ensure that the new code does not break existing functionality.

Regression tests can be run manually or automated, and there are various tools available to help with both approaches.

In simple words,  We do regression by re-executing the tests against the modified application to evaluate whether the modified code breaks anything which was working earlier.

Anytime we do modify an application, we should do regression testing (we run regression test).

Also Read: What is Retesting? When Do We Do Retesting?

Regression testing gives confidence to the developers that there is no broken functionality after modifying the production code.

It makes sure that there are no unexpected side effects. Hope you have understood what is regression tests. Now let’s see when do we do this type of testing.

Regression Testing Example

Assume there is an application which has a functionality to ‘Add’, ‘Save’, and ‘Delete’. These functions allow users to add data, save data and delete data. Now developers are developing a new feature i.e., ‘Update’. This feature allows users to edit and update the data. As a tester, you have to verify the introduction of a new feature (ie., Update) impacting the existing features (such as ‘Add’, ‘Save’, and ‘Delete’ functions) or not.

Check the below video to see “What is Regression Testing, when and how to perform it“

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What are the types of Regression Testing?

There are three types of Regression Testing.

1. Unit Regression
2. Partial Regression
3. Complete Regression

#1. Unit Regression

Unit Regression Testing is done during the unit testing phase and the code is tested as a single unit without any dependencies. Dependencies if any are temporarily blocked to test the unit independently.

In this, we are going to test only the changed unit, not the impact area, because it may affect the components of the same module.

Assume there is a form to accept user details such as First Name (accept only alphabets of max 10 characters), Last Name (accept only alphabets of max 10 characters), Emai Id (accept alphabets, numbers & special characters of max 30 characters).

Based on the test case design techniques, testers test the above form once the build is released.

Once the development team releases the build (B0001), testers start testing this build to verify whether the form is working as expected or not.

If the client request some modificiations in the form say the First name and Last name filed should accept max 15 characters instead of previously given 10 characters.

Developers will modify the functionality and release another build (B0002) and testers here test only whether the First name and Last name accepts max 15 characters or not and wont check any other features of the first build (B0001).

Here, testers are sure that the increase in the character count in the First name and Last name fields wont affect the form functionality, so they test only the character count.

Testing only the modified feature is known as Unit Regreession Testing.

#2. Partial Regression

Partial Regression Testing means when regression testing is done on a module where the change in the code is related to that particular module and there wont be any change impact on other modules.

It is also known as Regional Regression Testing.

Assume we have Login page along with User details form. If the tester finds a defect (D0001) in the form functionality and reported it.

Developers fix it and release another build (say B0003) which contains bug fix.

While testing the build (B0003), testers identify tha the bug fixing in the User details form impacts Login Page.

So testers test the bug fix first and then tests the Login page functionality.

Pro Tip: Whenever a build is released, as a tester you need to following the order – perform smoke test, test newly released features, test modified features, retest the bugs, test the impact areas by performing the regional regression testing.

#3. Complete Regression

Complete Regression Testing means when regression testing is done on a number of modules where the change in the code is related to the other module is uncertain.

It is also known as Full Regression Testing.

If there are new features and some bug fixes in a build. Test team will do the impact analysis. If they identify that the new build will lead to test the entire application then they perform testing the new features along with all the existing features.

Automated Regression Testing Techniques

Software maintenance is the process of modifying a software application which includes improvements, bug fixing, deletion of existing features, and optimization. When we do these modifications, the system may work incorrectly. To avoid issues while modifying the code, we do follow regression testing techniques. These techniques help us to eliminate the risks associated with the modifying code.

Following are the various techniques for automated regression testing.

1. Retest All
2. Regression Test Selection
3. Test Case Prioritization

#1. Retest All

All the test cases in the existing test bucket or test suite are re-executed to verify that there are no bugs that occurred due to the modified code.

This is a very expensive method as it needs enormous time as well as resources when compared to the other techniques.

#2. Regression Test Selection

By using the regression test selection technique, we select a part of test cases from the test suite to run to verify whether the modified code affects the application or not instead of re-executing the complete test suite. This selection of test cases from the test suite is done on the basis of the modified code. The test cases chosen are categorized into two parts such as reusable test cases and obsolete test cases.

Reusable test cases – Test cases that can be used in succeeding regression cycles.

Obsolete test case – Test cases that cannot be used in succeeding regression cycles.

#3. Test Case Prioritization

By using this technique, we select the test cases with high priority first to run instead of a medium and low priority ones. Test case priority depends on its business impact, frequency, and criticality. Running high-priority test cases first can save time and money while finding the most defects. This approach is especially handy when dealing with a large codebase.

Difference Between Re-Testing and Regression Testing

Retesting is a testing types to test the functionality or bug again to ensure that the defects which were found and posted in the earlier build were fixed or not in the latest build.

Regression testing is a testing types to repeat the testing of an already tested program, after modifications, to discover any defects introduced or uncovered as a result of the changes in the software being tested or in another related or unrelated software component.

Most of the time testers get confused with both regression and retesting. As a tester you have to remember that both these regression testing and retesting are different. You can read the complete list of differences between Regression Testing vs Retesting in detail here.

When do we do Regression Check?

Regression checks are essential when there are changes in the software that could potentially disrupt existing functionality. These checks help in ensuring that the updates or modifications do not introduce new bugs. Here are some scenarios where regression checks are necessary:

• After Bug Fixes: Whenever a specific bug is addressed, regression tests help us make sure that the fix didn’t accidentally impact other parts of the application.
  • Example: If a bug was fixed in the login functionality, a regression check would confirm that users can still log in successfully without issues.
• New Feature Additions: When new features are introduced, it’s crucial to run regression tests to verify that existing features continue to operate as expected.
  • Example: Adding a new payment method to an e-commerce site requires testing all previous payment methods to ensure they still function correctly.
• Code Refactoring: Whenever we make changes to improve the code structure without affecting how it behaves externally, it’s important to run regression checks to ensure everything still works as it should.
  • Example: Streamlining database queries to enhance performance should still yield the same results on the front end, which must be validated through regression tests.
• Software Updates or Patches: Updating libraries or frameworks can affect your application, so regression testing is a great way to make sure everything stays compatible and functions smoothly.
  • Example: Upgrading a library used for handling user sessions should be followed by checks to confirm that user authentication workflows operate without disruption.
• Environment Changes: When migrating the application to a new server or cloud environment, it’s a good idea to run regression checks to ensure everything went smoothly and that all functionalities are still intact.
  • Example: Migrating to a new hosting provider may introduce changes in configuration that affect application behavior, necessitating thorough testing.
• Performance Issue Fix: When we spot and fix performance issues, regression testing becomes really important to make sure those solutions haven’t unintentionally impacted other parts of the system.
  • Example: If optimizations are made to database queries to reduce load times, it’s vital to verify that other functionalities relying on those queries continue to perform correctly under expected operational conditions.
• Change Request: When stakeholders request changes to existing functionalities, thorough regression testing is necessary to ensure that the alterations do not introduce unexpected issues.
  • Example: If a user requests modifications to the user interface for a data entry form, regression tests should be conducted to confirm that the form still functions correctly and that no other parts of the application are inadvertently impacted.

By implementing regression checks in these scenarios, teams can maintain software quality and reliability throughout the development lifecycle.

How do we perform Regression Testing?

Steps to carry out to perform regression tests are

• Step #1: Get clear understanding on what are the changes made to the software
• Step #2: Analyse which part of the software might be impacted with the modified code
• Step #3: Make sure whether you have to follow which type of regression such as Unit, Partial, or Full regression.
• Step #4: Execute the selected test cases.

What is Automated Regression Testing?

Automated regression testing in software development automates the execution of regression test suites to ensure new code changes don’t harm existing functionality.

Automated regression testing uses specialized tools and scripts to automatically execute predefined test cases. It quickly identifies issues by running predefined tests. This method saves time, catches bugs early, and can be scheduled to run continuously, enhancing the product’s stability and reliability before release.

Why Automated Regression Testing?

Regression tests are generally extremely tedious and time-consuming.

We do regression after every deployment, so it would make life easy to automate test cases instead of running manually each and every time.

If we have thousands of test cases, it’s better to create automation test scripts for the test cases which we do on every build (i.e., regression testing)

Automated regression test is the best practice and it is the choice of organizations to save a lot of time and to run nightly builds.

When using automation for regression testing, it is important to consider the frequency with which the tests will be run.

For example, if the codebase is constantly changing, it may be necessary to run the tests on a nightly basis. Alternatively, if the code is only changed occasionally, it may be possible to run the tests less frequently.

It is also important to consider the impact of false positives when automation is used for regression testing.

A false positive is when a test incorrectly reports a bug or error.

This can happen for various reasons, such as changes in the environment, code that is no longer used, or incorrect test cases.

If false positives are not properly handled, they can cause significant problems, such as wasted time and resources investigating bugs that don’t actually exist.

How to Perform Automated Regression Testing

Performing automated regression testing involves several key steps to ensure the process is efficient and effective. Here is a detailed guide on how to perform automated regression testing in simple and easy-to-understand English:

• Identify Test Cases for Automation: Start by identifying which test cases are suitable for automation. Focus on repetitive tests that cover critical functionalities of the application. These could include previous bug fixes, core features, and areas most impacted by recent changes.
• Choose the Right Tools: Select appropriate automation tools based on your project requirements. Popular tools for automated regression testing include Selenium, QTP (Quick Test Professional), and JUnit. Consider the tools’ compatibility with the technology stack used in your application.
• Set Up the Testing Environment: Ensure your testing environment is stable and mirrors the production environment closely. Install all necessary software, libraries, and tools required to execute the tests.
• Create Automated Test Scripts: Develop test scripts that will perform the predefined test cases automatically. These scripts can be written in various programming languages like Java, Python, or JavaScript, depending on the automation tool you are using. Make sure the scripts are modular and reusable.
• Data Preparation: Prepare the necessary test data that will be used during the test execution. Ensure the data is realistic and comprehensive enough to cover various scenarios.
• Run the Tests: Execute the automated test scripts using the selected tools. You can schedule the tests to run at specific times, such as during off-peak hours or overnight, to avoid disruptions in the development process.
• Analyze Test Results: Once the tests have run, review the test results carefully. Automated tools often provide detailed reports highlighting which tests passed, failed, or encountered issues. Analyze these results to identify any bugs or discrepancies.
• Update and Maintain Test Scripts: Regularly update the automated test scripts to reflect any changes in the application. Maintenance is crucial to ensure that the scripts remain effective and continue to cover all critical functionalities correctly.
• Continuous Integration: Integrate automated regression testing into your continuous integration (CI) pipeline. This allows tests to be run automatically every time new code is committed, ensuring continuous validation of the software.

By following these steps, you can perform automated regression testing efficiently, helping to maintain the stability and reliability of your software through continuous and thorough testing.

Benefits of Automated Regression Testing

Automated regression testing offers several key benefits for software development:

• Saves Time: Running tests automatically is much faster than doing them manually. This saves time, allowing developers to focus on other important tasks.
• Improves Accuracy: Automated tests remove the risk of human error. They consistently perform the same steps and can be run many times with reliable results.
• Increases Test Coverage: More test cases can be executed in less time, ensuring that more parts of the application are tested thoroughly.
• Enhances Productivity: With faster and more accurate testing, the development team can release updates more frequently, keeping the software up-to-date and competitive.
• Provides Quick Feedback: Automated tests run every time new code is added, giving immediate feedback on any issues. This helps detect and address problems early in the development cycle.
• Ensures Consistency: Automated tests can be run in the same way every time, ensuring that the application behaves as expected across different environments and scenarios.

By leveraging these benefits, automated regression testing significantly contributes to a more efficient, reliable, and scalable software development process.

What are the Challenges of Regression Test Automation

There are some challenges in performing regression testing, even though it plays a crucial role in the QA process.

#1. Right Tool

Selecting the appropriate tool plays a key role in the success of regression test automation. If we select an inappropriate tool then regression test automation will become time-consuming and won’t generate good ROI.

#2. Resources

To utilize the selected tool in a proper manner to generate good ROI, we need to have skilled resources who can use the tool effectively.

#3. Time Consuming

Regression testing involves running the same test cases again and again. It leads to large test suites and consumes more time to complete the test execution. Sometimes due to time constraints, we may not run the entire regression test suite.

#4. Test Coverage

To overcome the time consumption, we have to minimize the test suites. We may not achieve maximum test coverage when minimizing the test suites.

Must read: Test Automation vs Automation Testing

Reasons Why Automated Regression Testing Could Be Right for Your Project

Automated regression testing offers several advantages that could make it the perfect choice for your project:

• Time-Saving: Automated tests run faster than manual tests, allowing you to complete your testing process more quickly. This is especially helpful for large projects with frequent updates.
• Consistency: Automation ensures that the same tests are run in the same way every time, reducing the risk of human error that can occur in manual testing.
• Cost-Effective: While there may be an initial investment in setting up automated tests, they save money in the long run by reducing the need for manual testers and catching defects early.
• Scalability: Automated tests can easily be scaled to cover more features and handle more complex test cases without a significant increase in effort or time.
• Repeatability: Automated regression tests can be run as often as needed without extra cost or effort, ensuring continuous validation of your software’s stability after every change.

What is Configuration Management During Regreesion Testing

In Agile Environments, Configuration Management in the regression testing becomes critical where code is frequently changed.

We must follow these steps in order to create a effective regression tests:

• During the regression test phase, no modifications should be permitted to the code. Developer changes must be kept out of regression test code.
• The regression test data must be kept isolated. No modifications to the database are permitted.
• The code being tested should be under a configuration management tool.

Must read: Configuration Testing Tutorial

Regression Testing in Agile

Now adays, most of the organizations are following Agile practices. Agile works in an iterative and incremental method. Developers work on new functionality and release them in every 2-4 weeks as sprint release. In agile, it is sure that for every 2-4 weeks once there will be a code change. In this case, the regression tests help in testing the new code change in every iteration to make sure that tested application continues to perform correctly after every iteration.

Best Practices of Regression Testing

Following are some of the best practices to be followed while doing this testing.

• Select the test cases that causes frequent defects.
• Select the work flow that has more visibility to the users.
• Conduct regression tests after smoke and sanity testing.
• Conduct regression tests at the end of functional testing.
• Have a regression test plan handy.
• Run regression test cases regularly to avoid the release risk in the next build.
• Use right tool to speed up the test process.
• Select all integration test cases, complex test cases, boundary value test cases.

Must read: Types of Test Cases To Be Automated and we Types of Test Cases Not To Be Automated

Automated Regression Test Tools

In most cases, the software undergoes frequent changes and we spent a lot of time to execute these regression test cases and which leads to high-cost and time consuming.

To avoid these problems we can choose automated regression tests.

Automation testing is a great way to run regression tests in efficient and cost effective way. It also helps testers not to test the repeated and boring tests.

In general, regression test suites have to be updated frequently. So while selecting a tool for your needs make sure the tool has the ability to update a test suite.

Here are some of the tools for regression testing that help you in automating your regression test cases efficiently and quickly.

#1. Selenium

Selenium is a free and open source test automation tool that is used to automate web applications. It can be used to test web-based applications on all major browsers, including Firefox, Chrome, Internet Explorer, Safari and Opera. Selenium can also be used to test mobile apps on Android and iOS platforms.

#2. Katalon

Katalon Studio is a powerful automated testing tool that can be used for both web testing and mobile testing. It supports many popular programming languages such as Java, Python, Ruby, Groovy, and C#. It helps testers save time and money by automating web, API, and mobile testing.

It comes with Katalon Recorder which acts as a record and playback tool.

Katalon Studio IDE supports the creation of test cases in Java and groovy.

#3. Ranorex

Ranorex Studio is a codeless test automation tool that enables testers to create, maintain, and execute automated tests for desktop, web, and mobile applications. Ranorex provides an all-in-one solution for end-to-end test automation, including support for Ranorex Studio – an integrated development environment (IDE) for creating and maintaining Ranorex test cases.

Ranorex also integrates with popular continuous integration (CI) systems such as Jenkins and TeamCity, making it easy to set up automated testing workflows.Ranorex supports testing on a wide variety of platforms, including Windows, macOS, and Linux. Ranorex tests can be executed on physical devices or emulators/simulators.

Must read: Best Regression Testing Tools

Advantages and Disadvantages

Advantages of Regression Testing

• It can be automated.
• Checks for code changes to ensure that they do not negatively impact other features.
• It improves the quality of the application.
• Ensure that already fixed issues and bugs are not repeated.
• During testing, it acts as a risk-mitigation approach.

Disadvantages of Regression Testing

• Regression testing might be time-consuming task without automating it.
• It must be done for every small change in the software code.
• We need to design complicated test cases to perform regression testing.
• Every time in an agile sprint, regression testing should be repeated.

Conclusion

Regression testing saves time and money. It helps organizations to deliver a quality product by ensuring that the code change should not affect the existing functionality.

FAQs – Automated Regression Testing Tools

Related posts:

• Manual Testing Tutorial
• Unit Testing Tutorial
• Integration Testing Tutorial
• Functional Testing Tutorial
• System Testing Tutorial
• Automated Visual Regression Testing Tools
• Visual Regression Testing Tutorial