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Deutsch Basics of regression testing: definition, benefits, application
During the software development process, a previously flawlessly functioning function may break down as a result of development changes. Without recurring checks, the bug can go under the radar - leading to extra costs, reduced security and user experience, and in severe cases, project delays. This is where regression testing can be of great help. In this article, we explain the concept, types and benefits of regression testing.
Regression test meaning: what is a regression test?
A regression test is a test to see if the functions that were already working are still working after the changes due to the development. It is an important part of the software development cycle and should be run after any major change. It helps to detect undesirable errors caused by a change at an early stage. IBM defines the meaning of a regression test as:
""Regression testing is the repeated execution of all tests to ensure that no regression occurs in the software. In other words, to ensure that correcting a bug does not cause another bug to occur in a previously working function."
While a study by the Budapest University of Technology and Economics uses the following definition:
"The purpose of regression testing is to make sure that previously working functions remain functional even after the changes made. This is usually achieved by re-running the existing test suite. Depending on the size of the system and the tests, this can take a long time, and can also check parts of the system that have not been changed.
Types of regression test
Corrective regression testing
Corrective regression testing is a software testing process that verifies that a particular bug fix does not cause a new problem or "regression" in existing software functionality. This method is chosen when implementing minor changes, when no changes have been made to the system requirements, so that existing tests can be reused without modification.
Retest-all regression testing
Retest-all regression testing is an approach in which all previously implemented changes are retested. Modules or program functions not affected by recent code changes may also be tested. This can be an unnecessary drain on resources and is therefore used when other regression tests have failed.
Selective regression testing
Selective regression testing checks only the parts of the program affected by the most recent code change to ensure optimal use of resources. Thus, only test cases that may have failed in the current development process are run.
Progressive regression testing
Progressive regression testing is used in cases where system requirements have changed over time. This may be due to changes in customer requirements or a development decision. In such cases it is necessary to create new tests.
Complete regression testing
In complete regression testing, all test cases are performed on the software. This can be useful when changes have been made to the source code. Also, it may be useful to perform full regression testing when several major code updates have been made to different modules.
Unit regression testing
The essence of unit regression testing is that the modules affected by development changes are tested in isolation from the program as a whole. Its main advantages are speed and minimal resource requirements.
What are the main benefits of regression testing?
Regression testing can have a number of unique benefits and is recommended for most complex projects. The following is a summary of the key benefits.
- It can significantly shorten the feedback cycle, which can even help you get to market faster.
- It can prevent costly and difficult to correct development errors.
- It can be automated, freeing up significant amounts of working time that can be reallocated to higher value-added tasks.
- It can help eliminate regression problems in development at an early stage.
A practical example of regression testing
In the following fictional example, we demonstrate when regression testing can be useful. During the development of a personal finance app available on iOS and Android platforms, a new feature is added: the ability to record incomes and expenses in multiple currencies. The app can graphically display spending data. However, an unforeseen issue arose during development: the app was unable to visualize historical data in multiple currencies. Due to diligent developers employing selective regression testing, the bug was identified early. The tester documented and reported the issue, which was promptly fixed.
Professional software testing
Since 2016, we have been involved in supporting, testing, and coordinating enterprise IT developments, as well as designing enterprise-level testing methodologies and automating business processes.As part of this, we facilitate the implementation of enterprise-level testing methods and the professional development of colleagues. Additionally, we assist in selecting and implementing necessary testing and ticketing tools. We also organize and conduct essential training sessions and demonstrations, prepare documentation, thereby ensuring efficient change management.
