Proposal of text for 'Composition of Assertions' subsection 'Scope of Inclusions'

[Stephen Green <stephen.green@documentengineeringservices.com>]

Proposal of text for 'Composition of Assertions' subsection 'Scope of
Inclusions':

"Scope of Inclusions

An umbrella specification usually relates to a referenced
specification by assuming or requiring
conformance of its implementation to this specification. These
conformance requirements can be
expressed in a test assertion's prerequisite or predicates.

The scope of this conformance may be determined by the expressions in
these prerequisites or
predicates.

The logical expressions used in the predicate may also include a
conformance requirement for varying
scopes of the (current) umbrella specification as follows:

· conformance to an (entire) umbrella specification

· conformance to a specific normative statement from the umbrella specification

Similarly, the logical expressions used in a prerequisite may also
include a conformance requirement for
varying scopes of the external specification as follows:

· conformance to an (entire) referenced specification

· conformance to a specific test assertion from an referenced specification

Consider the following case where the widget specification states that:

'All requirements in this section only apply to mini widgets, i.e.
Widgets that are conforming to the Mini-Widget Small Box specification
1.2.'

Then, in this 'mini widget' section:

[requirement 108] If a mini-widget has a battery holder, then the miniwidget
MUST be labelled as 'low voltage'.

The test assertion could read:

TA id: widget-TA108-1
Target: Widget
Normative Source: specification requirement 108
Prerequisite: [the widget] is conformant to the Mini-Widget Small Box
Specification 1.2 AND [the widget] has a battery holder.
Predicate: [the widget] is labelled 'low voltage'.
Prescription Level: mandatory

Note: If there are known test assertions for the Mini-Widget Small Box
specification
1.2 then the prerequisite text could be replaced with a list of
external references to
those test assertions. This has the added advantage of allowing a
partial inclusion
where a target in the umbrella specification is conformant to just a
subset of the
normative statements (and their test assertions) in the referenced,
external specification."

-- 
Stephen D. Green

Document Engineering Services Ltd



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