Formal Conformance Testing of Systems with Refused Inputs and Forbidden Actions

The article introduces an extension of the well-known conformance relation ioco on labeled transition systems (LTS) with refused inputs and forbidden actions. This extension helps to apply the usual formal testing theory based on LTS models to incompletely specified systems, which are often met in practice. Another topic concerned in the article is compositional conformance. More precisely, we try to define a completion operation that turns any LTS into input-enabled one having the same set of ioco-conforming implementations. Such a completion enforces preservation of ioco conformance by parallel composition operation on LTSes.