Regression testing: what it is, how it works and when it is essential

What is Regression testing

Regression testing is a type of software testing useful to verify the correct performance of the software after the implementation of a new feature or bug fixing. In such cases, the dependency between new and existing features may be high and lead to unexpected malfunctions. Therefore, in order to ensure the quality of the software, it is essential to verify that the new code does not affect the existing functionalities.

How the regression test works

Regression testing aims at solve a common problem that developers face on a daily basis: the appearance of old bugs with the introduction of new changes. If a project does not have strict version control systems in place, it will be difficult to trace which change introduced the problems encountered.

The working mechanism of the regression test includes a number of techniques that can be used:

• Retest All: involves the entire software. This approach requires the use of automated testing tools or the support of external users, because if it is carried out by the development team, it is unfeasible in terms of both time and money.

• Regression Test Selection: This is an alternative technique that consists in testing not the whole software, but in selecting some of all the test cases in order to approximate an average coverage. The main advantage is that it requires less time and effort, and can be managed both within the development team and by external users.

• Regression Test Prioritisation: The ultimate goal is to cover a limited set of test cases with different priority levels. Test cases assigned with a higher level are run first before moving on to less critical ones.

Automated tools are also available to support developers in their testing processes, which can be programmed as required. This means that if developers have a number of test cases available and, at the same time, the expected results are known, it is possible to automate the regression test.

However, the process of adding and updating test cases is a very complex activity. In particular, with each new release, developers find themselves with the burden of updating the various test suites on the basis of the changes made.

Regression testing, when is it essential?

One of the most common mistakes companies make is to consider regression testing as a kind of retest. The retest is nothing more than a process of checking and verifying parts of the code so that they are consistent with expectations. Regression testing, on the other hand, ensures that the entire system is capable of meeting the requirements before the release, guaranteeing that no new defects are introduced.

In teams adopting a software lifecycle management with Agile or DevOps methodology, regression testing is an integral and essential part of an effective continuous release. A very important aspect is to have the right balance between coverage and release timing. Each individual test must be adapted according to the needs and targets. Therefore, the first step is to become fully aware of the changes made so that the testing can be planned.

However, developers have limited time at their disposal, and in the development process, where updates are constant, this represents a major obstacle. Very often, test cases that are certain to have a positive outcome are selected or prioritised. This behaviour is also a direct consequence of the fact that the development team is already familiar with the code and the overall functioning of the software. The end result will not allow the discovery of potential bugs that could actually compromise the functioning of the software.

One solution to overcome these problems is crowdtesting. The necessary regression tests can be carried out by relying on a heterogeneous community of testers, available on-demand, characterised by a "fresh eyes" approach.

This leads to more accurate test cases thanks to the variety of devices and configurations, but also to a faster process that allows you to focus on the code.

A further benefit of using crowdtesting is also on the economic front, as testers are rewarded through payment on commission in order to minimise costs.

More effective regression testing with crowdtesting

Combining regression testing and crowdtesting results in a competitive advantage for companies, saving time in finding bugs and maximising the productivity of each team while decreasing the overall costs

Performing in-house regression tests from the beginning of the SDLC (Software Development Life Cycle) is no longer sufficient. There are countless devices on the market and different software configurations in the disposal of users. Not only that, but when a project grows significantly, the number of tests increases accordingly, making it impossible for the development team to verify requirements manually.

The answer to this high level of complexity is to carry out regression tests on a case-by-case basis using both crowdtesting and Test Automation. Thanks to the ability to integrate and make these two different methods coexist, it is easier and quicker to achieve the final result, which is to guarantee the best possible quality for each release.