What is unit testing primarily used for?

Unit testing is primarily used to evaluate individual units of source code. This type of testing focuses on the smallest testable parts of an application, usually functions or methods, to ensure that each unit performs as expected. The main goal is to validate that each unit of the software correctly implements its intended behavior. By executing these tests, developers can catch and fix bugs at an early stage of development, which leads to higher software quality and easier maintenance.

Other activities related to the choices, such as improving user interface design, enhancing system security, or debugging network connections, are different aspects of software development that do not directly relate to the evaluation of individual units of source code. These areas involve broader considerations and methodologies that are distinct from the focused approach of unit testing.