Description: The System Under Test (SUT) refers to the specific component or system being evaluated during the software testing process. In the context of Test-Driven Development (TDD), the SUT is the main focus, as all tests are designed to validate its behavior and functionality. A SUT can be a complete application, a module, a class, or even a function, depending on the level of granularity desired for evaluation. The importance of the SUT lies in its ability to allow developers and testers to concentrate on a specific area of the software, ensuring that each part works correctly before integrating with other components. This not only helps identify errors early but also facilitates the creation of automated tests that can be run repeatedly throughout the development lifecycle. In TDD, the SUT is developed in short iterations, where tests are written first, the necessary code is implemented to pass those tests, and then the code is refactored, all while keeping the SUT as the focal point. This methodology promotes higher software quality and a better understanding of system requirements, as each test is directly related to a specific functionality of the SUT.
