What does unit testing involve in software development?

Unit testing plays a crucial role in software development as it focuses specifically on verifying the functionality of individual components or functions within a program. The primary goal of unit testing is to ensure that each part of the code performs as expected in isolation from the rest of the application. By testing smaller, manageable pieces of code—called units—developers can identify and fix issues more easily, leading to improved code quality and reliability.

These individual tests allow for greater confidence in the codebase as each unit is evaluated against specific requirements or behavior. When a unit test passes, it signifies that a particular piece of code is functioning as intended, which can help prevent defects from propagating into more complex integrations.

Unit testing is different from other forms of testing, such as integration or system testing, which evaluate how components interact with each other and the overall functionality of the application. Additionally, it does not cover aspects like performance evaluation or security implementation, which are addressed through different testing methodologies.