Seven Types of Regression Testing
How the types of regression testing protect existing functionality in their own ways.
Key Takeaways
Within regression testing, there are seven different types of tests.
Each test focuses on the same goal (identify bugs, flaws, and issues), but with varying approaches and use cases.
Whether you’re using one or all seven approaches, regression testing can be amplified with Predictive Test Selection.
While regression may seem tedious and time-consuming to some developers, it’s also critical during the software testing life cycle. Regression testing helps devs continually assess app functionality, throughout the entire development process, which helps to avoid major issues down the line, and their subsequent costs.
Within regression testing, there are seven different types of tests. Each test focuses on the same goal (identify bugs, flaws, and issues), but with varying approaches and use cases.
Unit regression testing
What is a unit regression testing? Unit regression testing tests individual units of source code to determine if they are fit for use. A unit can be a single line of code, function, class, method, procedure, module, or object. Unit regression tests are best for small tests, as they provide a granular view of how code performs.
When is unit regression testing performed? Unit regression tests are performed during the coding phase of an application.
What are the drawbacks of unit regression tests? Unit regression tests take time to write and can require maintenance. Unit tests can also be difficult to craft for legacy
What are the benefits of unit regression tests? First and foremost, unit regression tests help to find and fix bugs early on in the software development life cycle. Down the line this saves time, money, and developer’s headache. Unit regression testing also helps developers understand the testing code base, so changes can be made more rapidly. Finally, unit tests can also act as project documentation
Partial regression testing
What is partial regression testing? Partial regression testing ensures a system performs as it is supposed to be, new code is added.
When is partial regression testing performed? Partial regression testing is performed after new code is added to existing code, and after impact analysis.
What are the drawbacks of partial regression tests? Partial regression tests can be very time-consuming to run, as they must be run for every single code change, no matter how small. More complex functionalities also require more complex partial regression tests, which can eat up developer time.
What are the benefits of partial regression tests? Partial regression testing ensures a new “fix” or solution does not inadvertently negatively impact existing functionality. In this way partial regression testing protects existing features, so that they remain unaffected.
Selective regression testing
What is selective regression testing? Selective regression testing analyzes the impact of new code on the already existing code, as well as the effect of both new and existing code. Elements like variables and functions are incorporated into the app to identify results, without affecting the process.
When is selective regression testing performed? Selective regression testing is performed after new code is added in.
What are the drawbacks of selective regression tests? Selective regression testing demands extensive developer effort for manual testing and must be performed for every minor change in code.
What are the benefits of selective regression tests? Selective regression testing is applied when only select components must be retested. This can save developers time and resources, as compared to retesting the entire system.
Progressive regression testing
What is a progressive regression testing? Progressive regression testing ensures no features that exist in the previous version are compromised in an updated or newer version of an app.
When is progressive regression testing performed? Progressive regression testing is performed when new test cases and certain changes done in the program specifications are designed.
What are the drawbacks of progressive regression tests? Progressive testing is applied when new elements are introduced that require new testing environments or new test cases. Developing these new test cases can take up a lot of developer time.
What are the benefits of progressive regression tests? Progressive regression tests determine if updates or changes affect the existing components.
Corrective regression testing
What is corrective regression testing? Corrective testing is used in instances where there are no changes or updates to the source code, and the overall working functionality of the app must be tested.
When is corrective regression testing performed? Corrective regression testing is used when there are no changes introduced in the product’s specification.
What are the drawbacks of corrective regression tests? Re-running existing tests can be a tedious, time-consuming process for developers, who would be happier working on more interesting, high-level tasks like writing code.
What are the benefits of corrective regression tests? Corrective regression tests reuse existing test cases, which makes this kind of manual testing slightly easier for developers to perform.
Complete regression testing
What is complete regression testing? When multiple changes have been made to the code that affect the root code, complete regression testing is used to identify unexpected bugs.
When is complete regression testing performed? Complete regression testing is performed when multiple changes are made to the existing code. This kind of testing is most often done before launch, and can highlight if a new change has an effect on the root code.
What are the drawbacks of complete regression tests? Complete regression testing takes a lot of time! Additionally, this can be a massive test suite, which also adds onto testing cycle times.
What are the benefits of complete regression tests? Complete regression testing is one of the best software testing methods for identifying and understanding unexpected issues. Additionally, once this testing is completed, the final system can be made available to the user. One more benefit is if current features functionality needs to be tested, re-using existing test cases is possible.
Retest-all regression testing
What is retest-all regression testing? The most comprehensive of all regression tests, retest-all regression testing re-executes every single test scenario by using all of the previous test cases, to compare to the previous testing outcomes.
When is retest-all regression testing performed? Retest-all regression testing is performed when you want to rerun all of existing tests on the new code, to uncover the regressions.
What are the drawbacks of retest-all regression testing? To put it bluntly: retest-all regression testing takes forever, is quite tedious for the testers in charge, and can end up wasting a lot of time. All of those factors can ultimately lead to missed deadlines or a delay in release.
What are the benefits of retest-all regression testing? Despite what we just said, retest-all regression testing does carry some benefits. Retest-all regression testing ensures new source code changes don’t create issues for the app’s overall functionality.
Automate regression test selection for faster, reliable release
Automating your regression testing speeds up your testing pipeline. Increase your velocity further with Predictive Test Selection. Automatically select the best, most important regression tests for your team to run, based on predictability of failure.
Launchable uses your own git commit metadata to analyze your test suites through the Launchable CLI. Predictive Test Selection dynamically reorders your tests and identifies the most critical tests to run, based on code changes. Then, Launchable runs your tests for your within minutes.
Additionally, Launchable’s Test Insights offer data to monitor your regression test entropy, and gets rid of the need to run your entire test suite. With Launchable, you can automate your pipelines, deliver feedback to developers faster, and improve developer experience.
Less regression testing + faster regression testing times = happier devs.
Launchable’s Machine Learning platform can help you intelligently select regression test subsets and save your DevOps team valuable time and resources.
