Software Architect's Handbook

Interoperability testing

In addition to unit and system testing the two systems that must interoperate, it is critical to perform integration testing between the two systems. Tests must be conducted to ensure that the consumer system can locate the other system and that they can exchange information properly.

The testing environment should be as close to what will be experienced in production as possible. Keep in mind that, even if both systems follow a particular standard for interoperability, and even if both systems have passed their own conformance tests based on those standards, it is not uncommon for there to be issues with interoperability. Some issues may not be uncovered until both systems are tested together.