What is the main purpose of unit testing?

The main purpose of unit testing is to validate that individual components of the code perform as expected. This process involves testing each small, isolated piece of code—typically individual functions or methods—to ensure they behave correctly when given specific inputs and return the expected outputs. By doing so, developers can catch bugs and errors early in the development cycle, which can lead to more reliable software and easier maintenance.

Unit testing helps establish a clear definition of what each unit of code should do, allowing for quick identification of problems. This contributes greatly to the overall quality of the software, as it empowers developers to make changes in the code with confidence, knowing that they can run their tests to verify that no existing functionality has been broken.

While improving code performance, ensuring compliance with coding standards, and eliminating debugging efforts can be benefits of a well-tested system, they are not the primary goals of unit testing itself. Therefore, the focus of unit testing remains on confirming that each unit of code operates correctly under different conditions, making it an essential tool in software development.