Integration testing (IT) is the phase in software testing in which individual software modules are combined and tested as a group. It occurs after unit testing.
The modules of the component have been tested, in an integrated manner, in the test environment prepared, isolated and controlled.
The integration can be done in three different ways:
- Integration Top-down: requires that simulated the components of lowest level.
- Integration Bottom-up: requires that simulated the components of higher level.
- Integrating mixed (both previous techniques).
The simulations with other subsystems not yet ready are programs simulated using “ghost” called scaffolding (drivers, stubs).