Designing test cases for remote asynchronous testing is error-prone. This is due to the difficulty to foresee all the disorders on the observations collected by the tester as well as the possible collisions between stimuli and observations. Designing correct synchronous test cases is easier, but transforming .them into correct asynchronous ones is a difficult task. Moreover, it is difficult to compare remote testing and local testing as in general sets of conformant implementations are not comparable.In this paper, we prove that by the use of logical stamps, remote testing can gain the same power as local testing: the conformant implementations in an asynchronous environment are exactly the same ones as in a synchronous environment. We give an operational method to derive the correct test cases for remote testing with this testing power. Furthermore, we show that test cases designed for a synchronous environment can test synchronous conformance in an asynchronous environment. This is achieved by the implementation of a test driver executed at runtime on the tester.

This paper shows how the existing concepts of conformance testing can be used to define a formal framework for interoperability testing. First, the different possible interoperability testing architectures are discussed. Then, we define several interoperability relations based on the existing relations defined for conformance testing. A comparison of these relations is given, in terms of their power to detect non-interoperability. Some guidelines are given to help in generating interoperability tests.