Unit testing is a crucial practice in software development that involves testing individual components or functions of an application to verify that each unit performs as intended. These tests are typically automated and executed during the development process to identify and fix defects early, thereby improving code quality and reducing integration issues later. A unit test generally includes a specific set of inputs, the expected outputs, and assertions to validate the results. Unit tests can be written using various testing frameworks, such as JUnit for Java, pytest for Python, or NUnit for C#. By isolating each unit from the rest of the application, developers can ensure that changes or refactoring do not introduce new bugs. The benefits of unit testing include faster feedback loops, enhanced code reliability, easier debugging, and improved documentation of code behavior, making it a fundamental practice in test-driven development (TDD) and continuous integration/continuous deployment (CI/CD) pipelines.