What testing methodology focuses on individual components of the software?

Unit testing is a software testing methodology that specifically targets individual components or functions of the software to ensure they work as intended. The primary goal of unit testing is to isolate each part of the program and show that the individual parts are correct in their functionality. This typically involves testing minimal parts of the application, like functions or methods, often using automated testing frameworks.

By focusing on single units of code, developers can quickly identify and fix defects at a very early stage of development before integration with other components occurs. This leads to more reliable and maintainable codebase since issues can be resolved at the smallest unit level, reducing the complexity and time required to debug larger codebases later in the development cycle.

In contrast, other testing methodologies like integration testing examine the interactions between components, system testing looks at the entire system's behavior, and end-to-end testing assesses the application's workflow in a real-world scenario. Each of these methodologies plays an important role in software development, but none are specifically targeted at validating individual components like unit testing.