RE: ... coments on Section 3.7.2 "COmposition of Assertions" (V0.995)

["Durand, Jacques R." <JDurand@us.fujitsu.com>]

inline <JD>

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From: david_marston@us.ibm.com [mailto:david_marston@us.ibm.com]
Sent: Thursday, October 23, 2008 10:14 AM
To: Durand, Jacques R.; tag-comment@lists.oasis-open.org
Cc: stephen.green@documentengineeringservices.com; Kevin Looney
Subject: Re: ... coments on Section 3.7.2 "COmposition of Assertions" (V0.995)

JD>- in some of these cases, eligibility refers to another TA(s) - meaning to the outcome of the predicate of these TAs. It is more informative to "reuse" another TA in the prerequiiste Instead of just replicating the predicate expression: this indicates to test suite writers a way to avoid redundant testing.
It also indicates what is the impact of failing a TA on the outcome of other TAs (so that users can make the difference between a "naturally unqualified" target and a target that is not qualified because it failed a previous TA where it should have passed it.

I agree with that principle. I was just trying to point out a couple hazards that must be avoided:
1. Circularity in the chain of dependencies  

<JD> indeed, it goes w/o saying people should not write circular sets of TAs... (worth mentioning in guideline)

Some processing (e.g. XSLT) over the TA mark-up should detect that.

 
2. Citing some other spec at the general notion of "conformance" as opposed to having the prerequisite tied to an actual TA from that other spec (which may be addressed by having a "summary TA" in the other spec)
I see emails that question what the prerequisite is trying to do in the context of citing another spec. Maybe the predicate is adequate in itself. For example, if all FooML documents must be well-formed XML documents, can't the FooML TAs just have a TA without a prerequisite...
Target: FooML document
Predicate: the document is a well-formed XML document, per XML 1.0
Is that an adequate example of one spec citing another?  

<JD> right for your example- and maybe we should have one simple, no-prereq example.

We need to also  illustrate the case where a prereq is used  :

 e.g. requirement 1 = "a  FooML document MUST be well-formed XML1.0"

requirement 2 = "a  FooML document MUST include an <author> element as first child"

Then we can have for TA2 using TA1 as prereq:

Target: FooML document

Prereq: TA1 (or we could have just "[FooXML" is a well-formed XML according to XML1.0")

Predicate: [FooXML] has first child = <author>

 

..................David Marston
IBM Research