Functional testing: Types, examples, and 5 best practices

Functional testing is a critical process in software development that ensures a system or application operates as intended by verifying each feature against predefined requirements. This testing method encompasses various types, such as unit testing, which examines individual components, and sanity testing, a quick check of specific functions or bug fixes. Regression testing evaluates the impact of new code changes on existing functionalities, while smoke testing assesses the stability of a new software build. Integration testing focuses on the interaction between different application components, and usability testing reviews the user interface and overall user experience. Functional testing differs from nonfunctional testing in that it verifies the correct operation of features, whereas nonfunctional testing assesses performance metrics such as scalability and security. Together, these testing approaches help identify issues that could affect user experience, ensuring that both customer-facing websites and internal applications function smoothly and efficiently under various conditions.