  Deployment of distributed systems sets high requirements for procedures and
tools for the complex testing of these systems. This work introduces a formal
four-layered model for test generation mission on the basis of the
component-based approach and the concept of layered networks. Based on this
model, we describe the test generation strategy that covers every interaction
from the end-user requirements on all coexisting architectural layers, and
checks the internal consistency of the system technical specifications with
respect to the end-user requirements. The next step introduces the Prolog-based
approach to representing this model and the requirements-coverage strategy
