System Integration Testing(SIT) is a black box testing technique that evaluates the system's compliance against specified requirements. System Integration Testing is usually performed on subset of system while system testing is performed on a complete system and is preceded by the user acceptance test (UAT).
The SIT can be performed with minimum usage of testing tools, verified for the interactions exchanged and the behaviour of each data field within individual layer is investigated. After the integration, there are three main states of data flow:
Data state within the integration layer
Data state within the database layer
Data state within the Application layer
Intra-system testing
Inter-system testing
Pairwise testing
Top-down Integration Testing
Bottom-up Integration Testing
Sandwich Integration Testing
Big-bang Integration Testing