System Integration Testing

System Integration Testing (SIT), in the context of software systems and software engineering, is a testing process that exercises a software system's coexistence with others. System integration testing takes multiple integrated systems that have passed system testing as input and tests their required interactions. Following this process, the deliverable systems are passed on to acceptance testing.

Systems integration testing (SIT) is a testing phase that may occur after unit testing and prior to user acceptance testing (UAT). Many organizations do not have a SIT phase and the first test of UAT may include the first integrated test of all software components.