Testing can focus on various aspects of a system or software. These aspects can include a focus on functionality, or what the system does, or on non-functionality, how the system does it what it does. It can also include testing on the system’s structure, changes to the system, if changes are successful, and if any unintended side effects happened. These four levels of test types are called functional, non-functional, structural, and change related. In this post, I will examine functional testing and testing pertaining to changes.
Functional testing involves testing the specified behavior or “what it does” and may be performed at all test levels. Specification-based testing is also known as “black-box testing” since it tests without reference to the internal structure of the component or system (Black, 2012). The testing focus for functionality testing is usually suitability, interoperability, security, accuracy, and compliance, according to ISO 9126 standards. There are two main approaches to using this test type: requirements-based or business-process based.
Requirements-based testing can take the requirements from the table of contents of a specification document and use them as a test basis for creating the tests. Business-based requirements are focused more on use cases from business processes. In a payroll system, for example, business processes would include when an employee joins the company or how often employees are paid.
Testing related to changes involves confirmation and regression testing. After a failed test, a defect is found and fixed. Confirmation testing involves re-testing the code in the same way and make sure that the new code did not bring in any unintended side effects and can be used at all test levels. Regression testing is used as a follow up to confirmation testing.
Regression testing involves executing test cases that have already been completed and most likely passed the last time they ran. We must organically grow the regression test suite over time in line with the software just as we do with unit tests. Should one of these tests now fail, we will have found a new defect introduced to the system. Regression testing should be performed at all test levels, specifically when a new version of the software is created, or the software environment changes.
Black, R. Foundations of Software Testing ISTQB Certification. [Capella]. Retrieved from https://capella.vitalsource.com/#/books/9781305175594/