What is Regression Testing? Meaning, Tools, and Types
Regression testing is a high-stakes activity: if your application falls after you make one change, imagine what would happen if you add ten more! Read on to learn everything you need about regression testing - from its importance to challenges and more.
What Is Regression Testing?
Regression testing is a vital process that checks if the existing functionalities of software still work as expected after any changes have been made. The process involves retesting the functionalities previously tested to identify any defects or changes that affect the system′s stability or functionality. The purpose of regression testing is to ensure software stability and reliability during development or maintenance.
Example: A software team develops an e-commerce website. The testing team creates 1000 test cases to check every aspect of the application. After adding new features or updates, the QA team does regression testing by creating 100 new test cases and re-executing the previous 1000. This ensures the website works as intended and maintains software quality.
Why Regression Testing?
Regression testing is a critical testing practice or method that helps maintain software stability, minimize risks, and ensure that changes made to the codebase do not negatively impact existing functionalities.It is vital in delivering high-quality software that meets user expectations and business requirements.
Types Of Regression Testing
The following are the different types of regression testing that are commonly used in software development.
Corrective regression testing is used when no modifications are made to the product′s specification.
Retest-all regression testing verifies all system specifications from the origin and reviews every minor change the software has experienced.
Selective regression testing identifies how the code behaves when new code is added to the existing code and utilizes a subset of current test cases to lower the effort and cost needed for retesting.
Progressive regression testing yields significant outputs when specific modifications are made in the program and new test cases are developed.
Complete regression testing is used when numerous updates are performed on the existing code or when the new updates have a distinct impact on the overall software.
Partial regression testing validates issues when new code is pushed to an existing one and ensures that a system functions as expected.
Unit regression testing is conducted in isolation and mainly focused on code units without any dependencies and interactions.
When Can We Perform Regression Testing?
Regression testing is performed by testers in the following scenarios:
- When new functionality is added to the software application.
- When there is a requirement to change.
- When a defect is fixed.
- When a functional/performance issue is fixed.
- When there is a change in the environment.
How To Choose A Regression Testing Software?
When you're on a hunt for an automated regression testing tool for your project, you will have to take a look at these key factors and ensure that the tool aligns with them,
Factor #1: Simple yet efficient test creation
Creating tests needs a proper understanding of the application under test (AUT) and strategic thinking. The time taken to create tests varies depending on the complexity of the application and the testing approach. Does your regression testing tool simplify the test creation process?
Factor #2: Faster test execution
The core reason for shifting from manual to automation for regression testing is the speed. Is your tool capable of accelerating your testing?
Factor #3: Easy test maintenance
When the application undergoes code changes, the test cases must also be updated accordingly. So, does your tool simplify test case/script update and maintenance?
Factor #4: Self-healing capability
How easy is it to update your tests if your applications go through changes? Does the tool have a built-in self-healing feature to minimize test failures after the application changes?
Factor #5: 24×7 Technical support
Does the platform provide extended support for technical queries? Customer support is a major concern for most teams, as many testing platforms lack proper, active technical support.
Best regression testing tools
There are various regression testing frameworks and tools available in the market that cater to different testing needs. The following list explores the best tools for regression testing with their most celebrated features. Please note that they are not in order or priority or any other ranking.
Testsigma
Testsigma is a robust low-code, cloud-based, GenAI-powered test automation platform that allows you to automate web, mobile, API, desktop, and Salesforce testing. It is a unified testing tool that provides an intuitive yet powerful visual interface to automate regression tests and other functional tests for different application types from the same platform.
You can create automated tests in plain English, which makes it easier than ever for a tester (manual or automation) or even people from other backgrounds to write test cases.
You can create automated tests in plain English, which makes it easier than ever for a tester (manual or automation) or even people from other backgrounds to write test cases. When it comes to regression testing, Testsigma makes the testing process 10X faster, helping you ship products quickly. With features spanning from integrations of pipelines to incorporating in-sprint automation principles, Testsigma is a complete solution for all your regression testing needs.
Here is a quick look into the factors we discussed above,
Factor #1: Simple yet efficient test creation
You can quickly create test cases in plain English without writing any code using low-code testing approaches, such as NLP-based testing, Recorder, and Data-driven testing.
It is the only tool that supports code-based (Java) and codeless testing in one place, making it accessible for both technical and non-technical users to collaborate efficiently.
Factor #2: Faster test execution
Like test case creation, test execution is also faster with this platform. You can further speed up the execution with Parallel testing. You can quickly run multiple tests across multiple test environments simultaneously. Test your app across 3000+ real devices/tablets and 1000+ browser/OS combinations using the real device cloud.
Factor #3: Easy test maintenance
Editing code-based test scripts is challenging as you must understand the code and then update your scripts every time. But Testsigma simplifies the test maintenance process. You can easily edit and maintain test cases on the cloud. Since the test cases look similar to the natural language, automated testing is more accessible for new testers or other stakeholders on the project.
Factor #4: Self-healing capability
Testsigma supports AI-driven auto-healing capability to prevent or debug test failures. In several cases, the test case fails due to changes to the object properties, which might cause the entire test run to collapse. The auto-healing capability self-heals the test cases by automatically updating the elements without breaking them.
Factor #5: 24×7 Technical support
Testsigma offers 24×7 customer support via chat, call, email, and community. It is a crucial advantage if you need tech support at flash speed. Instead of waiting for someone to answer your queries on larger testing communities over the internet, you can look up to us for any technical support or queries. Our tech support team is available round-the-clock for any customer query.
Selenium
Selenium is a popular open-source test automation framework that supports web testing. It provides a strong automation library with methods that are easy to implement and execute on various browsers. Selenium holds a little over 45% of the market share and has been in the market for many years now. It helps enable regression automation, which executes test cases automatically and faster than manual methods.
Selenium supports all the major platforms. Also, it supports the execution of multiple tests at once using Selenium Grid. Since Selenium is only for web app testing, you will have to opt for other testing tools for automated mobile app testing.
- Factor #1: Selenium is a script-based testing framework and is popular for its long list of programming language support. You can create code scripts using any of the languages supported. However, testers require strong coding skills to create test scripts. Also, understanding, updating, or maintaining these test scripts gets daunting when a new tester takes over.
- Factor #2: Is test execution faster? Not as fast when compared with tools like Testsigma. That is because you need to install multiple tools and libraries to create and run Selenium tests.
- Factor #3: Is test maintenance easy with Selenium? No, it isn’t, as you will have to rewrite the test scripts every time the UI or code changes.
- Factor #4: Does it provide any in-built feature to prevent test failures? No, Selenium does not offer AI-driven capabilities.
- Factor #5: Factor #5: Does it provide extended technical support? Selenium has a very active and large community for any technical queries. But extended support, no.
testRigor
testRigor works on the same principles of codeless test automation as Testsigma listed above. Using the English language as the medium of instruction, testRigor enables manual testers to write and execute automation tests without any additional effort.
testRigor comes with its own Google Chrome extension that can capture the actions done on a web application and convert them to test cases.
A quick look at the factors,
- Factor #1: You can create tests using plain English, like Testsigma. English-based test cases are easy to read, and therefore, non-technical people like stakeholders can also provide their input.
- Factor #2: It claims to make the test execution faster.
- Factor #3: Having English as the script language has the biggest advantage of reducing the maintenance of the tests.
- Factor #4: Yes, it offers self-healing capabilities.
- Factor #5: It offers support through Slack and MS Teams.
Sahi Pro
Sahi Pro is a complete regression test automation tool to help build regression tests for web-based applications, mobile apps, and desktop applications. Sahi Pro is lightweight and can be used by people without technical knowledge as well.
It provides a spreadsheet-like interface where the tester or other persons can define the steps of the business flow. Once done, they can use the Sahi Pro recorder to record the interactions and create tests out of it. They can later be used for refinements and adding more value, preferably through data.
Let’s take a quick look at the factors,
- Factor #1: It provides a Recorder that works across most browsers, desktop, and mobile applications.
- Factor #2: To analyze the test results in-depth, detailed reports with graphical representations are presented that include summaries of execution as well. It helps quickly debug failures in regression tests and maintain them easily.
- Factor #3: When there is a code change, use the Recorder to automatically go to that particular point and record the new step, making test maintenance easy with much effort required.
- Factor #4: Yes, it has self-healing capabilities that prevent test failures.
- Factor #5: Provides technical support via email and phone.
With all these benefits, Sahi Pro stands to be a good regression testing tool with an open-source nature. However, the open-source free version comes with very basic testing features that may not be able to fulfill your requirements every time. This is one of the downsides that should be kept in mind before finalizing this tool.
IBM Rational Functional Tester
If there is something that does not care about the type of application you have and can provide automation regression testing capabilities to everything is the IBM rational functional tester. Its vast range includes .Net, Java, and even terminal-based applications. It is popularly used in regression and GUI testing and is often referred to as a “rational functional tester”.
Since this tool is owned by IBM, it will provide seamless integrations across other IBM applications. This could be really helpful as a lot of work can be accomplished from a single screen rather than juggling between tools.
- Factor #1: Though the tool provides a record-and-playback feature, it helps technically advanced QA teams to write code faster. So, testers are required to have strong coding skills in order to use the platform.
- Factor #2: You can execute automated functional tests for web-based applications, including Java, .Net, Siebel, PowerBuilder, terminal emulator-based applications, and SAP.
- Factor #3: The ScriptAssure technology helps in keeping tabs on user interface changes. Hence, the changes can be easily tracked and modified in the scripts which in turn brings down the maintenance overheads.
- Factor #4: IBM does not provide any built-in feature to prevent test failures.
- Factor #5: It provides basic community support that is available for free for all the clients. Only their enterprise clients get to use their 24×7 customer support.
Katalon Studio
Katalon Studio is a low-code, easy-to-use, complete test automation tool that takes care of not only regression testing but the phases before and after it. The tool is built on top of Selenium and Appium, which ultimately brings their advantages, too, when we use Katalon.
It provides an integrated development environment for advanced script writing and execution. Also, it is compatible with lots of integrations and pipeline third-party tools.
Let’s take a quick look at the factors,
- Factor #1: Katalon supports low-code test creation, which is perfect for testers with basic programming skills. It provides an Object Spy feature that allows testers to capture test objects or use the built-in keywords to write test cases. For advanced and custom test scripts, Katalon provides an ID with features like code suggestion, syntax highlighting, and a debugger.
- Factor #2: It can be a bit slower when you have long test cases with hundreds of steps to execute. That is because Katalon uses Groovy, which is built on top of Java, and it needs to load many libraries to parse test data and objects.
- Factor #3: The tool comes with an in-built advanced debugger that helps debug errors in scripts faster than conventional methods. This helps reduce the test maintenance efforts.
- Factor #4: Katalon Studio provides self-healing tests that are automatically validated when there is a change or broken object.
- Factor #5: It offers support via its website and forum
Watir
Web Application Testing in Ruby, or simply Watir is a library for automating test cases written for Ruby applications. It is open-source in nature and is available as a RubyGems gem. For someone working on Ruby-based applications, WATIR is one of the most interesting libraries due to its nature of executing tests similar to how people operate on a web application. Recently, Watir webdriver was also introduced in the same series of library ecosystems.
People who do not want to work in Ruby or have experience in Python can also use its Python implementation called Nerodia. It is powered by Selenium but is in a very early stage.
Let’s take a quick look at the factors,
- Factor #1: It supports Ruby for test case creation. Also, it can only be used to automate browser interactions for web applications.
- Factor #2: Since Watir is built on top of Selenium WebDriver, it is a bit faster as it directly interacts with the browser.
- Factor #3: Since it is a code-based testing tool, maintaining test scripts can be quite a challenge for the testers.
- Factor #4: It does not provide any AI capability to prevent test failures.
- Factor #5: Watir does not provide extended customer support. You can use the documentation or community for queries.
TestComplete
Testcomplete has proved to be a versatile automation testing tool with characteristics that are hard to ignore. Strengthening its wide platform range to modern features, Testcomplete provides a solution to each type of tester according to their requirements. It is owned by Smartbear and is trusted by big multinational corporations.
Let’s take a quick look at the factors,
- Factor #1: Testcomplete provides the platform for testers who love to write scripts and those who do not. With this flexible approach, you can also mix up the test cases by focusing on scripted methods for easy ones and choosing to go codeless for complex scenarios.
- Factor #2: Testcomplete can be run on desktop, mobile, or web applications written in different programming languages.
- Factor #3: Apart from automated testing, it lets you write manual test scripts and run them on the platform. However, it does not offer any assistance with test execution.
- Factor #4: It does not have any separate built-in feature that helps detect test failures or understand why the test failed.
- Factor #5: It provides an active community and professional support for technical assistance.
Ranorex Studio
Ranorex Studio is another test automation tool that is great for regression testing. It allows testers to automate mobile, mobile, and desktop app testing. Ranorex provides a suite of software, including web driver, Ranorex Spy, and Ranorex API.
Let’s take a quick look at the factors,
- Factor #1: Similar to most of the tools listed in this post, Ranorex Studio is codeless and facilitates script writing and maintenance to a great extent.
- Factor #2: Ranorex studio supports parallel execution over physical and virtual devices, minimizing the execution time of tests. You can also leverage Selenium’s Grid infrastructure as Ranorex deeply integrates with the open-source tool. Once the execution is completed, a detailed, in-depth report is provided to the testers for quick analysis.
- Factor #3: It provides a maintenance mode to debug tests quickly. When this mode is enabled, the test execution is paused, allowing testers to analyze and correct errors.
- Factor #4: It provides a self-healing feature to reduce test maintenance efforts.
- Factor #5: It has a support and help center for users seeking professional help with Ranorex.
Testlio
Testlio is a testing platform that allows you to connect with real-world testers for software testing solutions. Testlio is not a test automation tool like the others on the list, as it is quite different. It is a SaaS platform that connects you with testers globally to offer QA solutions. To put it precisely, it is a networked testing platform. Let’s discuss how it satisfies the factors,
Let’s take a quick look at the factors,
- Factor #1: It is not a test automation tool like Testsigma, Selenium, or Cypress. If the testers or the organization feel the need to collaborate with Testlio’s testers, they can do that within the platform. They can combine manual and automation or share the test case writing among themselves. Anything and everything is open for discussion as the team feels comfortable.
- Factor #2: It does not provide a dedicated platform to execute tests. Testlio integrates with all the popular testing frameworks and integration platforms, such as GitHub and CI/CD tools, to provide a smooth interface for testing. Testlio works with hundreds of testers on real devices with real browsers (not emulators) and on AWS farms to provide higher coverage and minimize the chance of a device-specific bug at the user’s end.
- Factor #3: Testlio is not a test maintenance tool or offers support for maintaining tests.
- Factor #4: Testlio does not provide AI-driven capability to boost your test processes.
- Factor #5: Testio support offers solutions regarding the SaaS platform where you network with testers. It does not provide support like Testsigma or Selenium, where you have a dedicated team of support to help you with your testing queries and the tool.
How Should One Choose Test Cases for Regression?
Identifying test cases for regression testing is important because it helps testers focus on critical functionality and avoid re-executing the same tests repeatedly. By prioritizing test cases, we can reduce the cost and time required for test execution, detect faults early on, and ensure the delivery of an exceptional quality product.
According to Priority:
- Select test cases with frequent defects
- Choose test cases with critical functionalities
- Select test cases with frequent code changes
- Cover end-to-end test flows
- Cover field validation test cases
- Select a risk-based testing approach
According to Techniques:
Customer requirement based priority: Test cases prioritized based on customer requirements, complexity, and volatility. Higher factor values prioritized.
Code coverage based technique: Prioritization based on the portion of code covered during testing. Major part of code tested first.
Cost-effective: Test cases prioritized based on cost factor, including regression testing, requirement gathering, test execution, analysis, and prioritization costs. Lower cost cases prioritized.
History-based: Prioritization based on test execution history, likelihood of selection determined by previous results.
Priority using fault severity: Requirements prioritized based on fault severity, higher weight given to code with potential for more faults.
Weight of requirement determined based on various factors, not specified.
Regression Testing Techniques
There are several regression testing techniques that can be applied based on the nature of the software and the changes being made. Here are some commonly used regression testing techniques,
1. Regression Test Selection
In this method, we select specific test cases from the test suite for the feature that has to be retested based on the changes made to the code. The test cases are categorized as reusable and obsolete. Reusable test cases can be used again in future regression cycles, while obsolete test cases are no longer used in upcoming regression cycles.
2. Test Case Prioritization
Instead of re-testing all test cases, this technique focuses on identifying and prioritizing the most critical test cases.
3. Re-test All
This technique involves re-testing the entire set of existing test cases.
4. Hybrid
This is a combination of Regression Test Selection and Test Case Prioritization methods. That is, instead of selecting the entire test suite, we only select the test cases that are re-executed based on their priority.
5. Corrective Regression Testing
It helps ensure the existing code works correctly and checks if the current test cases are usable. When the test results turn positive, QAs can be confident that the test cases are effective and up-to-date. It also allows QA to proceed with test planning and prioritization while incorporating new code changes into the testing process.
6. Progressive Regression Testing
It is a testing approach where QAs recognize that code changes may require changes to the test suites. So, they will work on updating the test scripts to align with the new requirements. This method is used when a change affects the product vision.
7. Selective Regression Testing
Selective regression testing is performed to observe how the code behaves when new code is added to the program. Here, a subset of test cases is selected based on the impacted areas of the software that have been modified.
8. Partial Regression Testing
Partial regression testing helps identify issues that may arise when newly written code is integrated into existing code. It ensures that the application's performance has not been impacted because of new code.
Regression Testing Best Practices To Follow
There has been a lot of debate among testing professionals regarding how many regression checks are necessary. A low amount of regression may lead to bugs being missed in production, while too much of it can burden testing teams. Therefore, it is crucial to strike a balance that provides adequate test coverage through a combination of a thorough approach and several best practices for regression testing. These practices are listed below:
1. Reduce Regression Impacts – Plan Small & Frequent Releases
As Regression issues may occur because of the changes done to the existing application code; hence the more the code changes in a release, the more would be the probability of increased regression impacts.
The development team should be encouraged to release frequent code changes to the testing environment.
2. Understand the AUT/Product better
It is important for the QA team to have a thorough understanding of the application in order to identify areas that may be more susceptible to issues resulting from new changes. One way to achieve this is by preparing story cards for each module and connecting them to show the relationship between them. This will make it easier to determine which module will be affected by changes made to another module.
3. Involve QA in Code Reviews
It is highly recommended to include the Quality Assurance (QA) team in code reviews. While they don′t need to scrutinize the code in detail, it is beneficial for them to have an understanding of the areas that were modified. This knowledge can aid in identifying areas that require continuous updates and facilitate the detection of regression issues in the future.
4. Dev-QA Pairing
Apart from being involved in code review, QA can also collaborate with developers during the development of new modules. This provides an excellent opportunity for the QA teams to take notes and plan their regression suites, ensuring maximum test coverage for the release.
5. Use Defect Tracking Systems to Document
In today′s agile development environment, where there is a focus on more frequent software releases, it is crucial to keep track of any issues that arise during testing. This information can then be used to create regression test plans. One of the best practices for regression testing involves addressing the problem of insufficient documentation. To do this, the issues should be documented in detail with supporting evidence, which can later be used to create automated test cases.
6. Identify the Regression Test Coverage Right
To identify regression test candidates, consider the high-risk areas, core features, and basic workflow of the application under test. It′s also helpful to include test cases that uncovered defects in previous cycles. Rather than exhaustive testing, create a logical set of test cases. Keep the regression test suite updated as the application evolves.
7. Automating Regression Suites
Grooming the regression suite is an ongoing process that starts when the application is launched and continues indefinitely. The suite may consist of thousands of test cases to achieve comprehensive test coverage. However, if done manually, this can create a huge workload for the test teams.
To avoid this, it is recommended to deploy an automation tool framework to run the regression packs and quickly report any code changes that break the application to the development teams. This approach significantly reduces testing efforts and enables the identification and resolution of issues in a timely manner.
Difference between Retesting and Regression Testing
Retesting and regression testing are two distinct testing activities that serve different purposes in the software testing process.
Here is a detailed comparison - Re-testing Vs Regression testing
| Criteria | Re-testing | Regression Testing |
| Definition | The process of executing test cases that failed in previous test cycles to verify if the issues have been fixed. | The process of re-executing selected test cases to ensure that the software still functions correctly after any new changes have been made. |
| Purpose | Focuses on executing test cases related to fixed defects or failures. | To ensure that the software still works correctly and that existing functionalities have not been negatively impacted by the changes. |
| Scope | Focuses on executing test cases related to fixed defects or failures. | Focuses on executing test cases related to the new areas of the software. |
| Test Cases Selection | Only the failed test cases from the previous test cycle are re-executed. | A subset of test cases is selected based on the impacted areas of the software that have been added/modified. |
| Test Type | Uses the same environment as the previous test cycle. | Uses an environment that closely resembles the production environment, including hardware, software, and network configurations. |
| Test Data | It may require specific test data related to the previously failed test cases. | It may require a range of test data to cover different scenarios and ensure adequate coverage of the impacted functionalities. |
| Test Execution Order | The failed test cases are given priority and executed first. | The test cases related to the changed or impacted areas are given priority, followed by other relevant test cases. |
| Type | It is a planned testing | It is a generic testing |
| Timeframe | Typically performed immediately after the fixes have been implemented. | Performed after changes have been made to the software, usually during the regression testing phase. |
| Automation | You can not automate test cases for retesting | You can automate regression tests, and it saves time and effort. |
| Test Coverage | Focuses on the specific areas where defects or failures were reported. | Focuses on a wider range of test cases to cover the impacted functionalities. |
| Time Taken | It is not much time consuming as it tests only the test cases related to bug fixing | It is quite time-consuming as it tests the overall functionality of the software |
| Bug detection | It makes sure that the original fault is corrected. | It checks for unexpected side effects. |
Conclusion
Regression testing is named as such because it involves testing to ensure that the software does not ′regress′ or return to a previous state where issues were present. It aims to verify that new code changes or bug fixes made to the software do not introduce new bugs or cause the existing functionalities to break.
Frequently Asked Questions
What is Regression Testing Explain with Selecting Cases?
Regression testing ensures that the codebase changes do not affect existing software functioning. The code updates might include new features, problems resolving, or recent feature updates.
Few scenarios of selecting cases:
- Scenarios with many defects
- Scenarios for testing the fundamental properties of the product
- Case examples of functionality that have recently undergone major changes
- All Test Cases Integration
Is regression testing agile?
Which is the best regression testing tool?
Why testsigma is best regression testing tool?