Software integration testing is a phase in the development of a computer program where different components are merged and tested if they will interface flawlessly. In software development, different modules are created by several developers. These modules have different functionalities and application. The individual modules are tested by their developers. Once it passed this unit testing stage, each module will be integrated into a single functioning program. It will be tested then in order to determine if these individual modules will interface flawlessly.
If the interface suffers no glitches, then software integration is achieved. This is a critical phase of the development because the integrity and functionality of the software will be determined if its individual component could interact with each other. If the software fails the integration testing stage, then unit developers would have to rewrite their program and develop its capability to interface with other applications.
Usually, software development project leaders will carry out integration testing based on simulated end user behavior. The software will be deployed on a workstation and loaded with processes that mimic actual usage. This is a positive testing process because it tries to achieve software integration and functionality based on its expected output. If the positive integration test has been carried out successfully, the next step would be to calibrate testing by determining the extreme limits of the application. This test will determine if the integration process will still work if the software is subjected to stressful usage. After integration testing, the software will now be ready for systems testing and final deployment.