Although not a one-size-fits-all solution, regression testing can help many development teams address quality issues that can potentially lead to project failures. Read this article to explore the wide variety of regression test types that can be leveraged to maintain software quality.
Regression testing categories based on test execution
One of the major ways of categorizing regression testing is based on the ways test scripts are run. The conventional way incorporates running tests manually, whereas a more modern approach relies on automated test execution empowered by dedicated software.
The ability to conduct tests automatically can significantly simplify regression testing, which requires evaluating the application after any modifications, whether those are introduced to fix defects or update the software product. The more complex and larger the application is, the more effort it requires for regression testing. In certain scenarios, for instance, in the case of extensive software suites like Microsoft Dynamics 365 enterprise resource planning (ERP) and customer relationship management (CRM) suites, manual regression testing is virtually impossible.
Automated regression testing software ranges from frameworks like Selenium, which requires coding skills to set up a testing infrastructure, to no-code solutions like Executive Automats which are ready to use (https://www.executiveautomats.com/resources/articles/5-types-of-regression-testing).
Despite the powerful capabilities of automated regression testing, it cannot completely substitute manual testing, with the latter still used whenever decisions require human judgment, including usability regression testing and exploratory regression testing.
Types of regression testing based on test coverage
Regression testing that covers all areas of the software is known as complete regression testing. In contrast, testing that involves running all existing test scripts is referred to as retest-all regression testing.
Even though there are such comprehensive regression testing approaches that offer the most detailed software assessment, achieving complete test coverage for most software products is virtually impossible, even with automated tools. While manual testing relies entirely on manual effort, automated testing tools often require the manual creation of test scripts, demanding effort and resources and necessitating the prioritization of certain software areas over others.
Some of the most popular types of regression testing using test case prioritization are:
- Change-based testing focused on areas directly affected by recent changes;
- Risk-based testing that prioritizes areas with the potential for significant impact on business logic or application functionality;
- User journey-based testing that targets areas frequently used by end-users or critical to user experience;
- Regression testing using historical data that leverages past defect data to identify potential risk areas in new modifications.
Alternatively, automated regression testing can focus on test cases that are optimal for automation. These typically are critical cases, cases featuring higher stability and requiring repetitive execution.
Types of regression tests based on assessed software aspects
While regression testing primarily focuses on identifying defects introduced by code modifications, it can be focused on various aspects of an application. Although many of these tests are conducted separately from the regular regression testing routine, they can be used as a part of regression testing to further enhance overall software quality. Some types of regression testing based on this categorization include:
- Regression unit testing that ensures the correct functioning of isolated methods and functions after code modifications;
- Regression UI testing that evaluates whether the layout and UI elements have been adversely affected by application changes;
- Integration testing that assesses the interaction between different services and modules post changes, emphasizing API calls and data exchange validation;
- Compatibility testing that checks the software’s performance across different browsers, operating systems, devices, and configurations;
- Database regression testing that examines data integrity and database performance to ensure critical functions like data storage, processing, and retrieval remain unaffected by code changes;
- Performance testing that simulates various conditions to evaluate software responsiveness and scalability after code modifications. For instance, load testing recreates real-world scenarios under peak load conditions.
- Security testing that verifies that code changes have not introduced vulnerabilities. Key areas of security regression testing include authentication, authorization, input validation, data encryption, error handling, and logging.
Conclusions
Regression testing can be categorized based on several features. The most fundamental categorization distinguishes between manual and automated regression testing based on the approach to test execution, with the first running tests manually and the second automating this process.
Various types of regression testing are also distinguished by their focus on different software areas, which determines test coverage. Although comprehensive regression testing, such as complete regression testing, can assess the entire software, it is challenging to perform in most business scenarios. This difficulty makes regression testing types that prioritize specific areas more popular.
Finally, similar to regular testing, regression testing can also be categorized by specific software aspects, such as performance and security regression testing.
