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Regression testing

Regression testing is a critical part of the software development lifecycle. When developers update code or add new functionality to software, regression testing helps to ensure that the new changes haven’t created issues with existing code or broken the software and its functionality in some way.

Regression testing essentially involves rerunning test cases that have already been executed to make sure software works as intended.

How regression testing is performed

While regression testing can be performed in a variety of ways, there are several essential steps that most testing protocols follow.

  • Identify changes in the source code. Whenever code is modified or optimized, developers or testers must identify the components and modules that were changed along with any known impact on existing functionality.
  • Prioritize changes and requirements. To make the testing process more efficient, developers should prioritize modifications and test cases based on product requirements, as well as on the modules and functionality that are most commonly affected by changes to the code.
  • Build a regression test suite. A regression suite is a collection of test scenarios that address the various functionalities that are important to the software. Regression suites are typically created from existing functional tests, unit tests, integration tests, and other test cases that have already been executed.
  • Select an approach to testing. While some testers use a manual approach, most development organizations will automate regression testing since regression tests must be repeated many times as software evolves. Automating the process accelerates testing and frees testers to conduct manual exploratory testing.

In Agile methodology, each sprint involves iterative changes in software that may cause problems with existing functionality. As a result, regression testing is critical to the Agile process. Quality assurance (QA) teams should ideally develop test scripts alongside each sprint to ensure that regression testing is executed in a timely way. Regression testing in Agile is typically continuous and automated to allow development teams to stay focused on innovating with new features and releases. By embedding regression tests into the Agile process, software teams can reduce the risk of defects and minimize the time required for developers to fix them.

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When is regression testing performed?

Regression testing should be performed at several points in the software delivery lifecycle.

  • When new functionality is added. Developers adding new code to a software product aren’t always fully concentrated on its compatibility with existing code. Regression testing can help identify any possible issues early in the development process.
  • When changes to existing functionality are made. At times, developers make changes to existing code that add or eliminate certain features. When this happens, regression testing can determine whether the changes have had any adverse impact on overall functionality.
  • When software is newly integrated with other products. When developers enable a piece of software to integrate with other applications or technologies, there’s a possibility that changes in the code could break or compromise existing integrations.
  • When software is updated. When software is optimized to improve performance, fixed to solve defects, or when patches are added, regression testing can help to make sure that the improvements haven’t created new issues.

Types of regression testing

  • Complete or full regression tests involve all or most existing test suites and may cover much or all of the software’s functionality. Complete regression tests are an ideal way to establish the stability of a software product and to ensure that it meets project requirements. While complete regression testing is the easiest way to make sure all defects are resolved, it is also more time consuming and costly and is typically reserved for scenarios when an application undergoes a major update.
  • Partial regression tests are performed on the part of a software product that has been modified and on adjacent modules that may have been affected. Testing teams can use certain approaches to make sure that a partial regression test produces solid results. Partial regression is a risk-based approach that balances the risk that an area of code may be affected against the time and resources required for testing.
  • Unit regression tests are performed on discrete units or modules that are isolated from any dependencies to ensure that the functionality of the unit still works.
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Benefits of regression testing

Regression testing can not only improve software quality but reduce the time and cost of fixing defects as well. Other benefits include:

  • Earlier detection of defects during a major update, helping to minimize the impact on customers and users
  • Allowing developers to focus on new functionality rather than reworking old bugs
  • Improved user experiences without introducing unintended side effects
  • Fewer unexpected risks. Regression testing can be an effective part of risk mitigation strategy that helps developers and companies stay on top of changes and problems before they become significant issues
  • Improved overall system performance

Tricentis tools for regression testing

With the industry’s #1 Continuous Testing platform, Tricentis is reinventing software testing for DevOps. Providing Agile test management and advanced test automation that is optimized to support 160+ technologies, Tricentis transforms testing from a roadblock to a catalyst for innovation.

Tricentis solutions for regression testing include:

  • Tricentis Tosca. Tricentis Tosca accelerates testing with an automated, no-code, AI-based approach to end-to-end test automation. Tosca breaks through the barriers created by legacy and conventional functional testing automation methods. With an innovative risk-based and model-based approach to test automation, Tosca simplifies end-to-end regression testing for 160+ technologies.
  • Tricentis Distributed Execution. Part of the Tosca solution, Tricentis Distributed Execution (DEX) streamlines regression testing by distributing automated test sets across multiple virtual machines, computers within a network, or in the cloud. Testers can specify which tests should be run in different contexts, while this Tricentis solution automates load balancing to achieve optimal distribution of test sets.

The Tricentis platform also offers a suite of additional testing solutions and QA testing tools that include data integrity tools, Jira testing tools, performance testing tools, software test automation tools, and tools for ServiceNow, Snowflake, SAP, Oracle, and Salesforce test automation tools.

FAQs

What is regression testing?

Regression testing is an approach to testing software that determines whether recent changes to code have broken the software or adversely impacted existing features within it.

What are the benefits of regression testing?

By performing regression tests after code has been altered, updated, or optimized, development teams can ensure that software continues to meet project requirements. Regression tests also enable bugs to be found and fixed earlier in the development process, helping to save time, avoid rework, and reduce costs.

What’s the difference between regression testing and retesting?

Retesting takes place after a bug has been addressed to make sure the defect is fixed. Regression testing is performed after new code or functionality is added to software to make sure that the changes haven’t broken existing functionality and that the new code doesn’t have unintended consequences.

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