Integration testing techniques (sometimes called Integration and test, abbreviated "I&T"[citation needed]) is the activity[1] of software testing in which individual software system modules are combined and tested as a group. It occurs after unit test and before system testing. Integration test takes as its input modules that have been unit tested, groups them in larger aggregates, applies tests defined in an integration test plan to those aggregates, and delivers as its output the integrated system ready for system test.