Unit Testing Versus Integration Testing

Software testing activities are described in terms of the scope of the software being tested. Unit testing validates small subroutines and functions. Integration testing validates complete programs or significant sub-program. Most formal testing research is currently at the unit level, whereas most industry testing is at the integration level. This unfortunate fundamental dichotomy means that researchers cannot easily understand practitioners’ problems, and that practitioners cannot easily use researchers’ results. Testing currently means one thing to industry and another to academic researchers, and this misunderstanding is widening rather than shrinking.