1. An orderly progression of testing in which software elements, hardware elements, or both are combined and tested, to evaluate their interactions, until the entire system has been integrated.

2. Integration testing is black box testing. The purpose of integration testing is to ensure distinct components of the application still work in accordance to customer requirements. Test cases are developed with the express purpose of exercising the interfaces between the components. This activity is carried out by the test team. Integration testing is considered complete, when actual results and expected results are either in line or differences are explainable/acceptable based on client input.