Regression Testing – Meaning, Types and Tools

It can be challenging to introduce alteration in a logical, large code base. The latest version of a website, web application, or app may malfunction due to an enhancement, bug fix, or addition of any new functionality. Although developers can resolve this issue via automated tests such as unit tests, this comprehensive guide on regression testing focuses on highlighting the alternate, more generic, and exhaustive solution. 

What is Regression Testing?

Regression testing is a popular software testing methodology that ensures the seamless functioning of software applications as desired after any optimizations, enhancements, revisions, updates, or code alterations by re-running the functional and non-functional tests. 

Today, the software development cycle incorporates regression testing as one of its fundamental parts. That’s because regression testing enables developers to identify and locate unanticipated errors or faults in any application that may happen due to expansion, improvements, or alterations of the pre-existing codebase.

Now that you know ‘what is regression testing,’ let’s learn why it’s important in a software development cycle.

Why is Regression Testing important?

It becomes crucial for developers to perform regression testing whenever there is an alteration or modification in the existing codebase. This is done to check whether the altered and updated code will have an adverse impact on the other software application components or functionalities. 

Furthermore, regression testing is important whenever developers incorporate new functionality into the software application. It is conducted by developers when a performance or functional issue/defect is resolved. 

Now that you know what regression testing is and why it’s important, let’s move on to the section where we will learn how it works. 

How does Regression Testing Work?

Regression testing techniques vary from one organization to another. Nevertheless, every organization has to follow these basic steps to perform regression testing: 

• Identifying and locating the alterations or modifications made in the source code.
• Prioritizing the recognized modifications and product requirements. 
• Selecting the test cases to re-run depending on the modified module of the source code.
• Deciding the execution time for the test case based on test scenarios. 
• Splitting and classifying the test cases into manual and automated ones.
• Ranking the selected test cases depending on the significance level (low, medium, and high).
• Conducting every test case separately 
• Scheduling a time to cross-check if the software application performs as intended. 

Regression Testing Types

The different types of Regression Testing are as follows:

1. Corrective Regression Testing
2. Retest-all Regression Testing
3. Selective Regression Testing
4. Progressive Regression Testing
5. Complete Regression Testing
6. Partial Regression Testing

1. Corrective Regression Testing

   It is one of the ideal regression testing types when no modification is done to the software application’s source code. Here, you’ll check if the existing system functions properly, and thus, you will test the current functionalities and their associated test cases. You won’t have to write new codes or test cases here.

2. Retest-all Regression Testing

   One of the best regression testing types – retest-all – re-deploys each and every test case in the testing suite to ensure no bugs are in effect due to the source code modifications. This regression testing typically requires a considerable amount of effort and time from the Quality Assurance team than other regression testing types.

3. Selective Regression Testing

   In this kind of regression testing type, the test coverage is confined to a pre-made group of selected test cases. So, instead of retesting the entire software suite, developers only need to test a few selected components.

4. Progressive Regression Testing

   This is one of the seven regression testing types performed to upgrade the testing requirements and develop new test cases. Typically, developers prefer this regression testing type when introducing and incorporating new functionality into the system. That’s because it enables the developers to check and examine that the alterations do not impact the old components.

5. Complete Regression Testing

   In this regression testing type, developers need to test the whole system in a single go. Like acceptance testing, here you’ll be checking whether incorporating one or more modules impacts and compromises the user experience. Complete regression testing is performed when the product is about to release. 

6. Partial Regression Testing

   Partial testing is among the most popular regression testing types where developers measure the impact of incorporating new functionalities into the system. For instance, they check whether incorporating a new source code line would impact the software product or not. Compared to selective testing, here, both the old and new functionalities are tested simultaneously. 

Regression Testing Methods

Now that we have learned what is regression testing let’s look at the different testing methods for it. Developers can perform regression testing with the aid of the following methodologies:

1. Retest all

   It is one of the widely used regression testing techniques where developers re-execute each and every test present in the existing test suite. This method can be costly for development teams as it necessitates huge resources and time. 

2. Regression Test Selection

   Despite executing a whole test-case suite, the developers execute a selected test-case suite while following this method. Here, the selected test case suites get categorized into two unique cases: 

   • Obsolete test cases: Cannot be used in succeeding regression cycles.
   • Reusable test cases: Can be used in succeeding regression cycles. 

3. Test case Prioritization

   In this method, the developer considers factors like frequently used functionality and business impact to prioritize the test case. There will be a reduction in the regression test suite with the selection of test cases. 

4. Hybrid

   This regression testing method integrates the fundamentals of the above-mentioned methods: regression test selection and test case prioritization. 

Regression Testing Tools

Regression testing tools are crucial in automating and optimizing the regression testing procedure while making it more comprehensible. Some of the tools widely accessed by businesses include: 

• Selenium
• Rational Functional Tester (RTF)
• Quick Test Professional (QTP)
• Ranorex Studio

• Selenium

  It is an open-source tool that organizations widely use to perform automated testing on their web application. Selenium is a go-to tool for performing browser-based regression testing. 

• Rational Functional Tester (RTF)

  It is a Java-based tool that organizations leverage to automate the software applications’ test cases. RTF is mainly used to automate regression test cases.

• Quick Test Professional (QTP)

  When it comes to Functional and Regression testing, developers prefer using this keyword-based, data-driven, automated testing tool. 

Learn more about trending technologies and tools in the software development cycle to become a master in regression testing and other operations in no time! 

Advantages & Disadvantages of Regression Testing

Now that we have understood what is regression testing and its types. Let us explore the advantages and disadvantages associated with it.

Regression Testing Examples

Here is a hypothetical example to help you better understand the importance of regression testing:

Let’s say you’re a software developer who recently got a project to develop an editing app. You adhere to the main client requirements and use basic features to build the initial. You now use 800 test cases to perform regression testing and ensure the editing app functions properly. 

Once the application clears all regression tests, you mail the copy to get feedback from the client. Although the client is satisfied, they ask you to add more features. Now, you develop the requisite features and incorporate them into the app. 

Since you incorporated new codes, you must perform regression testing again. So, you write and devise 200 new test cases and check the app’s functionality. 

However, in addition to these new cases, you’ll also have to perform regression testing on the old 800 test cases to ensure they won’t adversely impact the existing functionalities.

Conclusion

In this article we have covered what is regression testing, its types and benefits associated with it. To conclude, organizations focusing on deploying regression testing techniques will get the most out of the resources, time, and efforts it has been investing in uplifting the quality and performance of their software products. 

If you want to excel in regression testing and make a career out of it, the best way to get started is by enrolling yourself in an AI & MI course from HeroVired.