08:30 Dec 23, 2011 

Thank you everyone for your suggestions. A friend who has studied software engineering wrote the following:

A higher level of testing is integration testing or system testing. Integration testing tests that the system as a whole works properly, with each module performing its function. Theoretically, if the specifications for each module are correct and the module performs as per its specifications, then the modules should all work together properly. But this is something that must be tested.

The author wrote "integrazione/sistema", which I think means "integration/system". Integration means working together, and could apply to confirming the operation of many modules which, as a whole, make up a higher level function, but which might or might not make up the *entire* system. So "integration" refers to the operation of any group of modules working together (whether that group makes up the entire system, or just part of it); and "system" refers to the exact same idea, but for the *entire* "system" (however that happens to be defined for a project).