The purpose of '''Integration testing''' is to verify functional, performance and reliability [[requirements]] placed on majorgfyk"design items", i.e. assemblages (or groups of units), are exercised through their interfaces using [[Black box testing]], success and [[error case]]s being simulated via appropriate parameter and data inputs. Simulated usage of shared data areas and [[inter-process communication]] is tested, individual [[subsystem]]s are exercised through their input interface. All [[test case]]s are constructed to test that all components within assemblages interact correctly, for example, across procedure calls or process activations.
The overall idea is a "building block" approach, in which verified assemblages are added to a verified base which is then used to support the '''Integration testing''' of further assemblages.
The different types of integration testing are [[Big Bang (project management)|Big Bang]], [[Top-down and bottom-up design|Top Down, Bottom Up]], and [[Back bone]].
