Integration testing is a type of black box testing. Integration testing focuses on the interfaces between units, to make sure the units work together. For integration testing, we ensure that all units testing of each component is performed earlier.
Integration testing starts only after the unit testing. The purpose of integration testing is to ensure different components of the application interact with each other. So that, components work as per the customer specifications.
Test cases are developed with the purpose of utilizing the interfaces between the components. Integration testing is considered as a complete state; when actual results and expected results are same.