What is Regression Testing?
Regression Testing is one of the most popular types of software testing. It ensures that any changes or modifications in the code of the software do not affect the existing functionalities and the software works efficiently. The main objective of regression testing is to ensure that a particular software works well with new changes or functionalities. If the software does not work well after the modification, it is referred to as a regression defect.
Various parameters are considered while performing regression testing. These parameters are bug fixes, software enhancements, configuration changes, or replacement of any electronic component. However, the term regression in software testing implies re-testing the part of the software which remains consistent.
For every software testing process, test cases are executed to check the performance. In regression testing as well, test cases are re-executed to ensure the performance of the older functionalities with the software. Also, the new changes should not result in bugs.
This was a brief introduction to regression testing. This article will provide you with a complete guide on regression testing.
Need for Regression Testing
When any new functionality is added in particular software, there is a need for regression testing. Regression Testing helps developers to enhance the quality and performance of any product. If there is a need to change the code or modify the code, regression testing enables us to determine whether the modified or changed code works well and does not affect the existing part of the software.
If the code is changed and it affects the existing functionalities, the quality of the software may degrade. Hence, to ensure the standard and execution of any product, there is a need for regression testing.
How to perform Regression Testing?
Several methods for regression testing are available. But, it will be very beneficial to choose the best and efficient method that performs regression testing within less time. The following are the three efficient techniques to perform regression testing:
- Retest All: Retest All is one of the best techniques to perform regression testing. In this technique, as its name suggests, all tests in the test list are re-executed. As a result, it requires a long time and is very expensive.
- Regression Test Selection: Regression Test Selection is another effective technique for regression testing. This technique involves the execution of only selected test cases from the test list or suite. However, the test suite consists of two types of tests, usable and obsolete.
- Test Case Prioritization: Test Case Prioritization technique for regression testing is based on business influence and commonly used functionalities. As its name indicates, test cases having higher priority are executed first.
- Hybrid: Hybrid regression testing is a mixture of two testing techniques. In this type of testing, the functions of the Regression Test Selection and Test Case Prioritization are combined. Test cases that are re-executed based on their priority are selected.
Certain steps assist users to improve the efficiency of performing regression testing. These steps are given below:
- First, you should build a complete outline of the functionalities that a software, undergoing regression testing, possesses and you want to test them. All the functionalities listed down are referred to as test scenarios.
- The second step to be performed is to choose the approach of regression testing. You should select the approach that falls between the structured approach and the explanatory approach. The automation approach is very beneficial for testers to carry out regression testing more efficiently within less time.
- After you select the well-organized and structured approach, the next step is to select the test cases. There are various parameters based on which you should choose test cases. Some of them are as follows:
- Is the function useful for all functionalities of the software?
- Is it a core function of the software?
- Is the selected function new? Is it tested against other functionalities?
- The next step is to decide the frequency of the testing. In other words, how many times you want the regression test to execute. Whenever any change is made in the code, you should perform regression testing. But, in the case of large software, automation is the only approach.
Choosing Test Cases for Regression Testing
Choosing test cases for regression testing is very significant and an essential step to perform regression testing. Test cases enable testers to identify what should be done to particular software during testing. There are certain tips that you should follow while selecting test cases. They are given below:
- You should choose those test cases that have recent changes or modifications made. Choosing these test cases may result in higher chances of finding issues.
- Choose the proper test cases that work very well with particular software and satisfy the business requirements and meet the clients’ needs.
- There are some parts of software that fail frequently. So, you should choose test cases where there are higher chances of bugs or defects taking place.
- Select test cases that are present in that part of the software that is visible to users.
- All complex test cases are to be selected to test the complexity and quality of the software.
- All integration test cases
- Select those test cases that are the core of the software.
- All units of failed as well as successful test cases.
Regression Testing Tools
Automated regression testing is one of the best approaches that save time as well as the cost of regression testing. In this type of approach, testers can run past test cases on a new build. For example, there is a set of test cases, and executing it requires a long time. But, the tester knows the result. In such cases, automating this set of test cases is an efficient approach and also saves time.
It becomes difficult for testers to add and update regression test cases in the automation test suite. To avoid this manual task, several tools are available as functional as well as regression testing tools. Some of them are listed below:
- Selenium: Selenium is one of the best tools used as regression testing tools. The significant and primary function of this tool is to automate web applications for testing purposes. Additionally, it automates web-based administration tasks. There is a Selenium WebDriver that enables users to create robust, web-based, regression automation suites and tests.
- Katalon Studio: Katalon Studio is another robust, sturdy, and all-in-one test automation solution. It has a productive IDE to produce automated tests on all operating systems, browsers, and devices. It does not require coding skills and hence, beginners can use it efficiently. It has Out-of-the-box Jira integration. It is also integrated with CI tools, like Jenkins, Bamboo, Azure, and CircleCI.
- vTest: vTest is a functional as well as regression testing tool. This tool can verify, record, playback, and report tests. It performs automate function and regression testing tasks in no time. Also, it regulates product evolution effectively by producing modifiable tests. Any tester without any programming background can use this tool. It has an intuitive and user-friendly interface.
Regression Testing and Configuration Management
The term, configuration management, states about all the items that a particular software product is composed of. A software product is a composition of several items, like source code, test scripts, third-party- software, hardware, data, and test documentation. The configuration management can also be defined as ensuring that all these items work effectively and attentively in the entire software development process.
In regression testing, the role of configuration management is very vital in Agile environments. In Agile environments, the code is modified continuously and frequently. You should consider the below steps to check for a valid regression test:
- Any changes in the code are not permitted during the stage of regression testing.
- Any developer changes should not affect the regression test.
- Changes in the database are also not allowed.
- You should choose the database that is isolated for regression testing.
Difference between Retesting and Regression Testing
Retesting and Regression Testing, both are the two different terms and ideas. We have seen above what is regression testing.
Regression Testing is a software testing, which is performed when the code is changed or modified to ensure that changes made in the code do not disturb the existing functionalities of a software.
Now, let us discuss what Retesting means. Retesting is also a type of software testing. Retesting is carried out to ensure that test cases which failed during the final execution are now executed successfully after the software defects are repaired.
The following table will give you a detailed idea about the differences between retesting and regression testing:
|Regression testing is carried out to ensure that the changes made in the code do not affect the existing functionalities.||The Retesting technique is carried out to verify whether test cases that fail during the previous execution run successfully after the defects get fixed.|
|This technique is carried out whenever there is a change in the code of the software product.||This technique is carried out whenever the defect gets fixed.|
|The Automation approach for performing regression testing is very efficient.||The Retesting technique cannot use the automation approach due to uncertainty.|
|Regression testing is not done for the verification of defects in the software||The Retesting technique is usually used to verify defects in the software product.|
|It is planned to execute in some specific areas.||It is planned to execute on specific fixing of defects.|
Challenges in Regression Testing
While executing regression testing, there are several challenges a tester may face. Some of these challenges in regression testing are enlisted below:
- The major challenge in regression testing is it requires a lot of time. A tester has to carry out successive regression tests. So, this takes a very long time, and also the cost of testing may increase.
- Good communication is a must between the testing team, developers, business analysts, and of course, clients. If a client changes his or her mind and desires to have a change in the product. That desired change should be known to every person involved in the testing and development process.
- Meeting between tester, developer, and business analysts must be carried out daily for some specific period. This is essential to discuss the progress, failure, and defects of the software.
- Another major challenge is to determine the frequency of regression tests to fix bugs.
- Requirements of the client play a very essential role and also acts as a major challenge in regression testing. Each requirement is categorized as high, medium, and low priority.
Importance and Benefits of Regression Testing
Regression Testing is one of the most-used software testing techniques. This technique is used to expose the newly found bug or defect in any software after any changes or modifications are introduced in the code.
Below are the reasons why regression testing is important:
- It identifies new defects in the software after the code is modified.
- Stakeholders can get all details of the pass and fail test cases after the regression testing is done. This will enable clients to make sure that the quality of the product is good.
- Regression is very essential because customers can utilize the software with minimum defects and bugs in it.
Advantages of Regression Testing
- It encourages the improvement of software product quality.
- Regression testing will ensure that bugs and effects that are detected already will not occur in the future.
- Any change in the code of the software does not have any side effects on the already tested code.
- Regression testing used with integration testing is very useful.
Example of Regression Testing
Regression testing is used for two major reasons. One is when the change implemented to fix any bug or defect fails. The other reason is introducing a new bug or unfixing an old bug. Below are examples of regression testing:
- Bug regression
- Old fix regression testing
- General functional regression
- Conversion or port testing
- Configuration testing
- Localization testing
- Smoke testing
After considering all the aspects of regression testing, it is an effective method that saves time as well as the cost for enterprises for developing the software product. It is proved that regression testing saves around 60% of the time in bug fixing. Also, customers can enjoy the product with less or no bugs and defects in it.