Civil Engineering Reference
In-Depth Information
Fig. 6.3
Error removal cost
after development phase
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well as clarifying the original intention of its designer. Unfortunately, it is
not always possible to find retroactively unique expressions for that speci-
fication. Nevertheless, the test specification describes clearly the expected
behaviour and the limits within which conforming implementations must be
operating.
− Conformance tests are developed in cooperation of many companies and
persons. This may be possibly supervised by consortia. Clear limits between
compliant and non-compliant behaviour are defined. This effectively protects
against supplier-specific interpretation vagueness. Supplier tests, however,
check the supplier's interpretation of a “correct” behaviour.
− Clear instructions concerning the test-system implementation and the test
process ensure a standardized test execution, generating comparable results.
Therefore, all implementations are tested under the same constraints.
− While applying identical evaluation criteria, a high degree of correspon-
dence of different implementations is ensured. If the component specifica-
tion describes interoperable components, then the compliant implementations
very likely will be interoperable, too. However, the following paragraph
explains in detail why anyhow conformance tests as well as any other test
cannot guarantee interoperability.
− Implementations which do not correspond to the standard are reliably disco-
vered. The correctness as a whole cannot be proven, but there is absence of
failures in all areas which are covered by the test scenarios.
6.1.2.1
Relation Between Conformance and Interoperability
A conformance test provides evidence that the behaviour of an implementation of
a component exclusively and comprehensively complies with the corresponding
specification of that component. This fundamental issue is the reason for the above
statement that no conformance test can ever guarantee interoperability of con-
forming components: Conformance tests absolutely only focus on the component
