What is Regression Testing in Software Testing? [A Complete Definition]

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What is Regression Testing?

Regression testing is a type of software testing that focuses on verifying that previously developed and tested software functionalities still work correctly after recent changes, such as updates, bug fixes, or new feature additions.

Usually, regression testing is done after functional testing, but it is not necessary as conducting regression tests depends on the specific context and goals of your project. Depending on your requirements or goals, you can perform regression testing after the performance, security, integration testing, or other types of software testing.

Although, having a clear understanding of software testing types helps to check your software thoroughly against your specified requirements. If you are curious to know all the types of testing, check our detailed guide on different types of software testing.

What are the Key Objectives of Regression Testing?

Learn about the purpose and key objectives of performing regression testing.

Validate that previously working features still function correctly after changes have been made to the software.
Detect and prevent any unintended side effects or issues introduced during the development process.
Ensure that the software maintains its overall quality and reliability, providing a consistent user experience.

What is the Importance of Regression Testing?

Maintain software quality:
Regression testing ensures that software maintains its overall quality, performance, and stability as it undergoes changes, such as bug fixes, updates, or new feature additions.

This testing helps detect and address issues, preventing potential defects from affecting existing functionalities. Afterwards, when acceptance testing is done, and there are no or fewer issues detected by end-users. You are able to provide a quality user experience within the software.

Moreover, learn from this article about what is acceptance testing, how it benefits, and its importance.
Validate changes: Regression testing is essential for verifying that recent changes in the software have been correctly implemented and functioned as intended without causing unintended side effects. This process ensures that the software meets project requirements and user expectations.
Reduce risk: Regression testing helps mitigate the risks associated with critical system failures or security vulnerabilities by identifying and addressing issues early in the development cycle. It ensures that the software system remains robust and secure even as it undergoes changes.
Support continuous integration and deployment: In modern software development practices, such as continuous integration and continuous deployment (CI/CD), regression testing plays a crucial role. CI and CI practices allow the rapid and quick release of new software versions which are thoroughly tested and do not compromise the existing software system.
Improve customer satisfaction and trust: Regression testing allows for improving the user experience by ensuring the software’s functionality, reliability, security, and overall performance. As regression testing helps to identify the issues, so does the software application with fewer bugs resulting in higher customer satisfaction.

Which are the Different Types of Regression Testing?

There are several types of regression tests that cater to different scenarios and focus on various aspects of software changes. Here is the list.

Unit Regression Testing: This type verifies the individual components or units of the software after changes have been made, ensuring that modifications do not negatively affect the functionality or introduce new defects.
Partial Regression Testing: Performed when only a subset of the software’s functionality is affected by recent changes, it involves identifying and re-executing the most relevant test cases that cover the impacted areas.
Complete Regression Testing: This type involves re-executing the entire test suite to validate the software after significant changes or updates, providing the most comprehensive coverage to ensure all functionalities remain intact.
Selective Regression Testing: In this approach, only the test cases most likely to be affected by the changes are identified and executed, focusing on critical or high-risk areas and balancing the need for thorough testing with resource constraints.
Progressive Regression Testing: Performed when new features or functionalities are added to the software, it involves testing both the new and existing features to ensure that they work correctly together and that the newly introduced features do not adversely affect the overall system.
Retest-all Strategy: In this approach, all test cases in the test suite are re-executed after any change in the software, guaranteeing that no side effects of the changes are left untested, although it can be resource-intensive.
Risk-based Regression Testing: This type of regression testing prioritizes test cases based on their associated risk, focusing on areas where defects are most likely to occur or would have the most significant impact, allowing testers to concentrate on the most critical aspects of the software while balancing time and resource constraints.

Each type of regression testing has its advantages and trade-offs, and the choice depends on factors such as the scope of changes, available resources, project timeline, and the criticality of the application.

However, to ensure the 100% effectiveness of regression testing, you must first perform functional testing. So, before moving into regression testing, you can identify the issues or risks in the software’s core functionality. If you don’t know functional testing you can read our post on what functional testing is.

7 Common Challenges Faced in Regression Testing

Here is a list of the common challenges faced in the entire regression testing process.

Test Maintenance

Updating test cases to accommodate software changes, new features, and bug fixes can be time-consuming and error-prone, potentially leading to ineffective regression testing.
Insufficient Test Coverage

If test coverage is inadequate, it may result in undetected issues and an increased risk of software defects. Ensuring comprehensive testing of all application areas is crucial.
Test Execution Time

Regression testing, particularly for large software projects, can be time-consuming. Extended test execution times can cause delays in software releases and impact development schedules.
Test Environment Stability

Unstable test environments can produce unreliable test results and compromise the effectiveness of regression testing.
Test Data Management

Managing test data effectively is essential for successful regression testing. Poorly managed or outdated test data can lead to incorrect test results and wasted effort.
Automated Regression Testing Challenges

Implementing and maintaining test automation can be challenging due to issues such as tool selection, scripting complexity, and automated test script upkeep.
Prioritization of Test Cases

Deciding which test cases to execute during regression testing can be difficult when resources and time are limited. Prioritizing test cases based on risk, criticality, and likelihood of failure is crucial.

What are the Popular Regression Testing Tools?

There are several widely-used tools and frameworks that can help you perform regression testing more efficiently. Here are some of the most common ones:

Selenium is an open-source testing framework that is ideal for web applications. It supports multiple programming languages and browsers, making it highly versatile for different projects.
JUnit is a testing framework designed specifically for Java applications. It allows for the creation and execution of repeatable tests, ensuring the reliability of software developed in Java.
TestNG is an advanced testing framework based on JUnit and NUnit. It offers greater power and flexibility, making it particularly useful for extensive test suites.
QTest is a comprehensive test management tool that simplifies the organizing, tracking, and reporting of testing efforts. It offers a centralized platform for managing testing processes.
JMeter is an open-source performance testing tool that is great for assessing and gauging the performance of web applications. It helps understand application behaviour under different loads and conditions and identifies performance issues and optimization opportunities.

While choosing tools for conducting a regression test, you should consider specific requirements of the software application. As you select the right manual or automated testing tools for regression testing, you are able to perform regression testing perfectly. This way, you can maintain the performance and quality of the software application.