Software engineering got to the point where it became increasingly complex and expensive. The introduction of libraries, open-source frameworks, and cloud-based services were meant to decrease development time and costs. Ironically, that leads to the opposite outcomes sometimes: the possibility of something going wrong increases with more components added into the mix.
Regression testing helps QA engineers ensure that none of those components gets broken whenever a system undergoes even a minor software update.
We’ll attempt to provide some tips and insight in this article. You can always count on UTOR as an expert in regression testing services. Leave it to us – we know what’s involved!
What Is Regression Testing?
What is regression testing? The origin of the word “regress” means “going back to the previous state of something”. So regression testing is “perspective testing”, so to say – it’s carried out to verify whether any component of the system is affected by the latest update.
The foundation of regression testing is a proper test case (a set of testing conditions) that defines the scope and the testing approach. We covered that in more detail in our article dedicated to regression test selection criteria. But as a general rule, you want a test case that yields bugs as often as possible. Although it might take a significant amount of time to figure out the right testing type if you do so manually, we suggest you refer to the automation testing practices.
Types of Regression Testing
Regression testing comes in different types and forms. How do you pick the one that works for you? Think of your software development life cycle (software development and testing are interconnected) and specific updates that you’re planning to introduce. Here is a display of the common types of regression testing techniques.
Corrective Regression Testing
Corrective performance testing is appreciated for its simplicity as it requires fewer efforts. It reuses the existing test cases, given that no major changes in the product specifications have been made (no need to change a testing scenario).
Retest-all Regression Testing
As the name suggests, this is a complex testing approach that needs all the system’s components tested again from scratch. This test checks retrospectively every small change that’s been made since the very start. Sometimes, this approach is used when suspicions arise that something was missed (or wasn’t done right) during the previous testing stages. Under such circumstances, it can be more effective to retest everything from scratch than attempting to identify what went wrong previously.
It’s not a very common approach, giving the budget concerns; but it gives you more quality reassurance about the system’s current state.
Selective Regression Testing
This type of testing can be viewed as a middle ground between corrective regression testing and retest-all regression testing: it’s not as basic as the first one, but not as comprehensive as the latter one. Selective regression testing picks certain test cases from a set to inspect the affected parts of the code.
Progressive Regression Testing
When the established test cases are no longer useful, the newer ones get created. This is often a case when the product specifications are modified, so new test cases must be created to address the changing requirements. Progressive regression testing involves using new testing scenarios when the product vision is affected.
Complete Regression Testing
Many companies adopt the Agile methodology that encourages doing fewer but frequent updates. In real life, that’s not always possible: companies need to react quickly to the ever-changing client demands. Thus, large-scale system updates are possible (but not likely). But when they do happen, complete regression testing is performed: it’s a must when the root code has been changed.
Partial Regression Testing
You can view software development as building a LEGO house: you create separate blocks first, then you combine them, and you end up with an entire house.
Your separate modules might have been in development for a while. When you’re about to merge them with a shared code mainline, partial testing is performed, using primarily the existing test cases.
Unit Regression Testing
That is a straightforward approach that is focused on testing code as a single unit with all the dependencies, integrations, and interactions left outside the scope.
How to Improve the Effectiveness of Regression Testing
It’s all about using the appropriate tools and utilizing the best practices. We’ll try to shed some light on both of these aspects.
Use Automation Tools
Automation is the key when it comes to regression testing, so here are the most common tools at your disposal:
- Selenium. This is a popular choice as it offers wide range of benefits, including libraries, open-source frameworks, and support of C#, Java, Ruby, and Python. Can’t go wrong with it.
- Testcomplete. A great option for parallel testing: Testcomplete uses automated builds so no manual intervention is ever needed. It’s great for web, mobile apps, and desktop apps.
- TestDrive. This awesome tool is all about speed and simplicity: flexible, easily deployable, and dynamic. It provides a great deal of automation but provides some manual testing options as well.
- TimeshiftX. This app is literally your time machine: it allows you to do temporal testing by operating virtual time: you can inspect and test all the app changes retrospectively.
These testing tools are some of the UTOR favorites of all time. Try out to see if they would be a fit for your project.
Regression Testing Best Practices
Getting started with regression testing is not just about using the proper tools – it all comes with a little practice. Some mistakes are inevitable at the beginning, so here is what we learned from ours:
- Get a fresh perspective. Remember we emphasized on the importance of test cases? So make sure to keep them up-to-date so they reflect the current state of your application. That also includes new features added and specification changes. Running tests to validate the product aspects that no longer exist is just a pure waste of your QA efforts.
- Know what works for you. Those tests that give you consistent results on a regular basis – make sure to keep them running occasionally.
- Get your priorities straight. There are so many things that can get tested as far as your testing strategy is concerned. The high-load areas require more thorough testing as they incorporate crucial functionality to the system.
- Don’t run complete performance testing unless absolutely essential. Don’t set up another test every time a new build is deployed: minor changes typically do not require complete performance testing.
The Bottom Line
You need to get three things right to make sure your regression testing is on point. First and foremost, know when to apply the right type of regression testing (and don’t make it overkill). Secondly, get the power of automation by your side. And finally, follow the best practices mentioned above!
