What are the Different Types of Regression Testing?


Regression Testing Types, Tool and Requirement

When it comes to a software solution, it is essential to make regular improvements to the application’s functionality and features. As the lifecycle of a product progresses, it can be challenging to maintain a balance between iterative testing and sprint work (agile software development) and successfully prevent conflicts. This is where regression testing comes into the picture, allowing it to set the right balance between the two.

Regression Testing – Introduction

The type of software testing that focuses on finding software regression (defects from a fix that may have impacted other areas that have been working fine thus far) is known as regression testing. It helps in detecting and identifying defects or bugs when a new change is made to an existing system. It involves application testing during changes made in the following scenarios:

  • Maintenance
  • New release development
  • Debugging
  • Development spiral

It ensures that the software remains stable when any amendments are made to the code. It focuses on minimizing the risks of defects or dependencies because of any changes to the code. This testing is conducted after maintenance, changes to functionalities or enhancements are made to a product to ensure that there are no unexpected outcomes.

What are the Different Types of Regression Tests?

Explore the different types of regression tests and their key features:

Corrective Regression Testing

This type of regression testing is conducted on current test cases that involve no code changes. It takes lesser time in detecting bugs. It is known for its convenience and repetitive use.

Progressive Regression Testing

This type of regression testing has been in use for some time. It stands out for the series of benefits it offers, yet it can be a more complex process. Here, new test scenarios are developed according to need.

Progressive regression testing can run properly when the product has undergone a few changes. It is also recommended when developing new test scenarios. It allows the testers to conduct the required step within the updated version of the program without touching the current features.

Retest All Regression Testing

This is a comprehensive test, conducted to check any bugs even when code changes have been made in only certain parts of the product. Due to this reason, it is a time-consuming process. 

It is scheduled to test each element of the product in a fixed period. The process involves the reuse of all the test scenarios from the very start. It is focused on monitoring each change or update that may have been made in the previous testing process.

Due to the time consumed, retest all regression testing is usually not recommended for all products. While clients may not want to use it every time, testers can consider it occasionally because of its comprehensive approach.

Selective Regression Testing

As the name suggests, only selected test cases from a module are processed where there are changes in the code. There is no need for running the complete test. Based on the requirements, new codes can replace it during the process. Selective regression testing is conducted more commonly because of the benefits associated with it.

  • It makes it possible to test and comprehend the outcomes of the original code
  • It can be run to check the effect of both the new code and the current code, both being present at the same time
  • Functions, variables, and other common elements are included in the application whenever there are changes to the case. 
  • The process doesn’t get affected and it is possible to find quick results

Complete Regression Testing

Complete regression testing involves the examination of the current code and features before running any testing. It is usually used in cases where the project owner doesn’t want to make big or more changes during the testing.

This type of regression testing is mostly conducted when the current code undergoes lots of changes. It is beneficial for allowing you to restore any changes that may be done during the process. 

Complete regression testing is a promising test. It is also used as a standard in most organizations because of its ability to find unexpected bugs in a short period. Once this phase passes, the application is allowed to be used by the user.

Partial Regression Testing

This type of testing involves the selection of certain related modules that could have been affected by any changes in the code. It plays its role only in a tiny part of the process. 

It is often required to add codes to an application for certain reasons. Whenever such new codes get added to the current code, the testers will usually conduct partial regression testing instead of more elaborate tests.

This type of regression testing is typically recommended in a wide range of scenarios.

  • It makes it easier to detect important bugs within the current code
  • The testers can check bugs within the current code without an impact on the product
  • This form of testing helps in saving time

Running partial regression testing is an essential part of regressing testing. This is why it is commonly used.

Unit Regression Testing

This is also an important component of regression testing. Many software professionals consider it to be the most important type of regression testing. Every time code changes are complete within a unit, the tester again runs all the previous positive test scenarios. Because it focuses on the code in a single unit, it usually conducts it in isolation. 

When this test is run, the tester will block most of the dependencies and interactions (isolation). This is why it is usually conducted in nonpeak hours of low traffic hours. The outcome of the test is evaluated for identifying the testing conducted on the system. This type of regression testing is, therefore, conducted by experienced testers. It makes it easier for you to plan the process, as it allows you to determine the proper procedure.


Also Read: Top 7 Software Testing Trends to Watch out in 2020


Application of Regression Testing

Regression testing should be conducted during your project in certain scenarios. These scenarios or cases include the following:

  • When a new functionality of feature gets added
  • When there is an optimization of source code for improving performance
  • When the codebase is repaired to address defects
  • When the configuration is modified
  • When patch fixes are made
  • When performance-based issues are fixed

Need for Regression Testing

The process of software development is known for being time-consuming, as it requires the creation of an ideal architecture before the product is launched. Regression testing is essential because it is a component of this process. It helps in removing most errors on a continual basis.
It helps in detecting bugs during the early phase of deployment. This also contributes to cost savings. When bugs are found during the initial phase, it helps reduce further efforts for resolving issues.

How Does Regression Testing Benefit You?

In the current scenario, there are many ways in which you can benefit from regression testing. It is important to connect its benefits to different requirements. This helps in getting the most out of the process in relation to the product.

Some of the key benefits of regression testing are as follows:

  • It makes it easier to detect and identify bugs that may have formed because of a code change
  • It allows you to learn about the effects of making any changes in the operating environment
  • It helps improve product quality
  • It is always beneficial when an adding test is done to your software

Regression Testing Tools

Regression testing may be a process that consumes time, the QA team may still execute it in manual form. On the other hand, automation tools can help save more than half the time for running tests. They can also help in increased cost savings. Some of these popular tools include the following:

  • Quick Test Professional
  • IBM Rational Functional Tester
  • Water
  • Regression Tester
  • Selenium

When it comes to developing a quality application, regression testing plays an important role. It is a crucial component of the testing process in the development of a product. It ensures that if changes are made to a code, those changes are not going to make an impact on the current code, its features, or functionality. Regression testing is mostly implemented using automation tools, as mentioned above. The manual mode is time-consuming and human effort intensive.
The choice of the tool eventually comes down to the project specifications and requirements. The selected tool will also be checked whether it can update the test scenarios. This is an important consideration in this type of testing.
Regression testing allows you to detect the defects whenever new changes are made to a current system. It also allows you to learn about the effect of the changes on the separate old modules where no changes are made. While the above outline the methods, the experience of a test team goes a long way to determine, what to test, how to test and how much to test in determining the right and optimal regression testing strategy.


About the Author

QA InfoTech

QA InfoTech

Established in 2003, with less than five testing experts, QA InfoTech has grown leaps and bounds with three QA Centers of Excellence globally; two of which are located in the hub of IT activity in India, Noida, and the other, our affiliate QA InfoTech Inc Michigan USA. In 2010 and 2011, QA InfoTech has been ranked in the top 100 places to work for in India.

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