What is the focus of unit testing?

Unit testing focuses on testing individual components or modules in isolation to ensure that each part of the system functions correctly. This process allows developers to verify that specific pieces of code work as intended, typically by examining the smallest testable parts of an application, such as functions or methods.

By concentrating on these discrete units, unit testing helps to identify bugs early in the development cycle, which can lead to more robust software design. This approach provides immediate feedback to the programmer, allowing for efficient debugging and improving the overall quality of the code.

Testing the entire system involves broader perspectives, often referred to as system testing, which evaluates the complete application’s functionality. Testing the integration of different systems is aimed at ensuring that various software components or systems work well together and communicate properly. User acceptance testing focuses on verifying that the software meets the needs and requirements of end users, validating usability, and overall functionality from an end-user perspective.

Thus, the emphasis on individual components in unit testing distinguishes it from these other types of testing, making it essential for catching issues at a granular level before integration or system-wide tests are conducted.