What is the main goal of unit testing?

Unit testing is primarily focused on verifying the functionality of individual components or pieces of code, often referred to as "units." The main goal is to ensure that each unit of the software behaves as expected and produces the correct output for a given set of inputs. By isolating these units, developers can catch defects early in the development process, making it easier to identify where issues arise and helping to ensure that the code is working correctly before it’s integrated with other parts of the system.

This practice builds a solid foundation for software quality and reliability, as it allows for quick feedback during development. When unit tests are in place, they can be run frequently, especially after changes are made to the code, which helps maintain the integrity of that specific piece of functionality throughout the software’s lifetime.

While testing the entire application at once, evaluating user interface usability, or validating integration between different modules are important aspects of software testing, they do not encapsulate the specific aim of unit testing, which is distinctly concentrated on individual components.