FW: A Variables Example together with a Worked Example

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

 

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From: david_marston@us.ibm.com [mailto:david_marston@us.ibm.com]
Sent: Tuesday, June 17, 2008 9:20 PM
To: tag-comment@lists.oasis-open.org
Cc: Durand, Jacques R.; stephen.green@systml.co.uk
Subject: Re: A Variables Example together with a Worked Example

I like the newest example for 
variables, where geopolitical-location (a.k.a. locale?) is the key for more than 
one assertion. It may be longer than you wanted for just introducing the 
subject, but it shows the point that the variable can be reused. The part where 
the WEIGHTs are set make this use of variables look a little OCL-ish, which I 
consider a bad thing, but maybe there are operational efficiencies that offset 
the aesthetic concerns. There are "exogenous" values, such as properties that 
cannot be determined by testing, so maybe that concept can be brought into the 
mix. In this case, geopolitical-location is an exogenous variable, while the 
WEIGHTs are the other kind, endogenous variables. Before you can run tests 
derived from these TAs, you need values assigned to all the exogenous variables. 
The endogenous ones will be calculated when "resolving" the TAs, which is a 
combination of running tests and/or resolving TAs such as widget-TA100-7a. 
(Notice that widget-TA100-7a does not require an actual unit-under-test, only 
that you know which geopolitical-location you're testing.) 

This leads to the further question, which can be deferred 
until a later edition. Should the collection of TAs for a particular spec be 
accompanied by a complete list of all the properties? Or maybe it needs a list 
of all the exogenous variables. See Appendix F of the XSLT 2.0 specification [1] 
for a real-life example of a list of properties that must be reset for each 
unit-under-test. 

SDG>There are here three types of TA
>1. 
normal
>2. property definition
>3. variable definition 

Interesting. I wonder if the Prescription 
Level should be used to earmark type 2 or 3 TAs. To continue the example, since 
widget-TA100-7a does not require an actual unit-under-test, it is not really 
"mandatory" because it doesn't impose a constraint that a non-conformant 
unit-under-test can violate. It's more like a "definition" as Stephen observed. 
I think Prescription Level needs careful engineering. 
.................David Marston 
IBM Research 

[1] 
http://www.w3.org/TR/2007/REC-xslt20-20070123/#implementation-defined-features