The only way to verify this is to enter information into one part of the system and check to see if it is properly dealt with and reflected in other parts, or check to be sure all networked computers have access to all programs and information. For example, in a simple software package that provides for storage and retrieval of student information, enter student information in the data entry screens, and verify that you can limit access to the data as needed and generate a report from it. With instructional applications, make sure all computers used by teachers and students can access the software and use it as planned. For example, check to be sure that all student computers on the network can access a particular CD-ROM, such as one containing an encyclopedia. This integration testing often must be done repeatedly in order to verify that the system handles information properly.
Performance testing is the final stage.
Be careful not to confuse user approval with system functionality. If your new system involves interfaces to other external systems, the importance of planning, testing and carefully verifying that the new interface works cannot be overstated. A new or revised software application may not communicate with other software applications in the same way that the old application did. Your new system may need specifications for how other software applications will interact with it. Keeping all of the applications used by an organization compatible is a major challenge, just as is keeping all hardware compatible with the requirements of new software.