Software regression testing: advantages, disadvantages and most common techniques

In order to ensure that the software is running properly and that the user is satisfied with the product, it is necessary to check the system before it reaches the customer. Regression tests can be instrumental in this regard, and you can explore further details below.

Testing is an integral part of software development to ensure the safety and functionality of the system. A specific type is regression testing during development, which is used to verify the functionality of the software (ideally) after each change in the code, addition of a new function, occurrence and correction of other bugs and during downtimes in software development. Using functional and non-functional testing procedures, we can find and fix possible bugs or potential risks after updates and minor and major changes to the source code.

In functional testing, testers focus on testing the functionality of the system in terms of its requirements and business processes. Non-functional testing, on the other hand, is used to verify features that are not part of the software’s functionality. They can determine whether the system is secure, portable, able to respond to unexpected situations even under load, and whether it is optimized for the user.

Regression testing advantages and disadvantages

Like all testing types, software regression testing brings with it many positives and negatives. In addition to keeping the software running smoothly after modifying code or implementing a new feature, regression testing allows you to:

• quickly identify bugs that could cause significant problems in later stages of software development. After the bugs are fixed, the product is retested by testers. The quality assurance (QA) team then makes sure that the software works as it should and is then returned to the customer.
• reduce the costs incurred in development and its suspension due to possible problems in the system and their necessary correction later in the development.
• introduce continuous integration and automatic execution of test scenarios used in previous regression testing.

In the context of regression testing, we can also mention a few of their limitations. After each code change, the software should be tested to ensure its functionality and efficiency. However, this requires a lot of time, which can ultimately cause delays and prolong the entire software development process, thereby increasing the costs involved.

To automate or not to automate regression testing?

Manual regression testing is not only time-consuming but also requires a lot of effort on the part of the testers. On the other hand, automated regression testing will provide developers with immediate feedback on the functionality of the software and save the testing team a lot of time that would have been spent on manual testing.

However, automation testing is relatively expensive, tests can only be run within a pre-programmed timeframe, and may clash with other types of automation testing and tools. Both types of testing have their positives and negatives.

Regression testing techniques

There are several types of techniques that can be used to perform regression testing. The most common technique is to prioritize test cases. Within it, testers progress from the most serious cases to the most trivial ones. The goal is to first resolve bugs and issues that make the software unworkable, and then to address small, simple bugs.

When selecting regression tests, on the other hand, the tester focuses only on tests where there may have been a change in software behaviour since the last update, and reuses older and validated test cases. As for the re-testing technique, this focuses on retesting regression tests that have already been performed, but with new coding. However, this technique is time-consuming and is mostly used for extensive software modifications.

Test cases and their impact on the effectiveness of regression testing

Choosing the right test cases is crucial in regression testing to ensure the functionality and efficiency of tests. Hasty last-minute fixes, especially when time is running out, can encourage the use of the simplest test cases.

However, this can result in inadequate and inappropriate testing that does not reveal all the bugs and potential risks and ultimately only prolongs the testing process itself. It is therefore ideal to use test cases that:

• represent the most important features of the software,
• have previously successfully found bugs in the code,
• verify more visible, recently and more frequently modified features,
• are complex, integrative or focused on threshold testing.

How is regression testing different from other testing types?

As mentioned earlier, regression is performed by combining functional and non-functional testing procedures. Compared to functional testing, regression testing does not focus on whether the code behaves as it should, but whether code changes or new features work correctly with the original code. In correctness testing, testers aim to verify the functionality and stability of the code in the early stages of development, as opposed to regression testing, which takes place at the end of the development process or after each code change.

Smoke testing, on the other hand, helps to find primary bugs and minor problems in the software before a new feature or update is added, while regression testing is designed to find the causes of the problem and possible solutions after the code has been modified. To ensure the best possible user experience, regression testing should not be underestimated or neglected. It will make your software or application work properly and run as it should.

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