It is Black-box type of testing that is based on overall requirements specifications. It covers all combined parts of the system.
It is the testing of combined parts of an application to determine if they function together corretly.
SYSTEM TESTING: Several modules constitute a project. If the project is long-term project, several developers write the modules. Once all the modules are integrated, several errors may arise. The testing done at this stage is called system test.
INTEGRATION TESTING: Testing two or more modules or functions together with the intent of finding interface defects between the modules or functions.