Towards a foundation for FDT-based conformance testing requirements

The testability of a protocol standard is a property of the standard that reflects the degree of precision in developing universal interpretation of what it means for an implementation to conform to the standard, and the ability to exercise the implementations of the protocol standard for purposes of assessing their conformance to the standard ~ELG95a\. In this paper, we investigate the conformance testing requirements (CTRs) of a protocol standard that result from the formal specification of the allowed (dynamic) behavior of the protocol standard. We focus on those CTRs that are applicable to all the international Formal Description Techniques (FDT); more specifically, SDL, Lotos, Estelle, and ASN.1. We develop a distinction among Implementor's options, Implementor's Choice, and Non-Deterministic Choices as well as testing semantics for each of them. Then, we develop rules for the explicit and precise specification of these CTRs, and for developing a precise and explicit PIXITP. These rules are essential for facilitating the controllability and propagation of observability, consequently, enhancing the testability of the protocol standard.