Civil Engineering Reference
In-Depth Information
specifications. As such, a component specification could define a component which
is not interoperable with other components of its kind.
An undiscovered error in the component specification could result in compo-
nents conforming to the specification but, nevertheless, not working appropriately.
As such, the quality of implementations not only depends on the coverage and ex-
cellence of the conformance tests, but also depends significantly on the quality of
the component specification itself. This specification is responsible for the defini-
tion of a component with an appropriate functionality corresponding to the system
requirements. Failing this, the conforming implementations could not operate ap-
propriately as this was a contradiction to the specification.
As for the end customer, finally interoperability is the utmost goal; they mostly
require tests proving interoperability. However, this cannot be achieved by mere
testing. Nevertheless interoperability tests do exist, mostly connecting various im-
plementations under laboratory conditions resulting in the verdict “OK” or “NOT
OK”, when applying specific test scenarios. The value of this verdict, however, is
rather limited with respect to the applied test scenarios, as due to this concept, tech-
nically and practically it is not feasible to check any possible scenario. As such, any
effort claiming to
guarantee
interoperability by testing is dubious.
Assuming a specification is properly done, in general, the risk of non-interop-
erable specified components is low. Consequently, the chance for interoperability
is increasing with the degree of compliance between the implementation and its
specification. The compliance is proven by conformance tests.
As mentioned above, the quality of the specification is supported by develop-
ment of conformance tests while precisely analysing the component specification
and pushing for its non-ambiguous interpretation. As such, a high-quality compo-
nent specification and related conformance tests will result. The risk of non-interop-
erable components is estimated to be rather low, especially when findings from the
development of the conformance tests are fed back into the subsequent revision of
the component specification resulting in non-ambiguous statements. Unfortunately,
the constructive feedback very often does not quite easily have its effect, because
standards quite often rather quickly become “untouchable”.
In conclusion, conformance tests as well as any other tests cannot guarantee
absolute interoperability, but they increase the chance to it.
6.1.3
Test Methods, Test Standards and Test Rules
Various test objects require different implementations of test systems, especially
related to the coupling of the test object to the test system. Most of the test systems
are based on the principle of accumulating findings from experience in order to
come to better solutions. Many of the characteristics, excellence and advantages of
existing test systems can be transferred to other test systems.
The standard ISO 9646 (see [ISO 9646]) specifies conditions and the methodol-
ogy for the design and execution of conformance tests according to well-defined
