(1) [t]esting that ignores the internal mechanism or structure of a system or component and focuses on the outputs generated in response to selected inputs and execution conditions. (2) Testing conducted to evaluate the compliance of a system or component with specified functional requirements and corresponding predicted results.
[a] test designed to validate that a business process or activity accomplishes expected results.
The purpose of functional or "black box" testing is to verify that the system correctly performs specified functions. As such, the test team's ability to design the functional tests is limited by the completeness and precision of the functional specifications. Starting with these specified functions, the test team develops test cases using a range of valid input conditions and options as well as invalid or unexpected inputs. The test team compares the test outputs to expected outputs.