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Use case definition

From: Andrew Thackrah <a.thackrah@opengroup.org>
Date: Mon, 29 Jul 2002 16:27:00 +0100
To: www-qa-wg@w3.org
Message-ID: <20020729162700.C4908@hyperion>

Re Action Item A-2002-07-10-1 
There is an outstanding issue (#72, [1]) on the Spec. guidelines doc 
(07/22 version, [2]) relating to  checkpoint 1.2; the definition of a use 
case and the implication of it being normative.

  The problem is that there is no formal definition of what a use case is, 
and that this undefined  thing is being made normative. Anything that is 
normative in a spec. is important and so should  be defined carefully 
before inclusion.
   What is a use case? There are several definitions but I think that one 
that is closest to the  SpecGL idea of a formal user scenario involves a 
related sequence of actions or events,  quantified with standard inputs 
and expected outputs.
   In my experience a scenario is composed of a chain of lower level test 
assertions. (The purpose of the  scenario is often to verify 
interoperability, something not easily done at the 'atomic' level of an  
assertion.)
  This implies the existence of low level, testable assertions being 
available before a use case can  be defined - and this overlaps with 
Guideline 15 and the idea of test cases.  So I think we need to answer the 
question   "Is a Use Case the same thing as a Test case?"   If not, how is 
it different?
   To make a start at answering this I'll note that the UML style of use 
case includes actors with specific  roles. The various 'users' to which 
SpecGL scenarios might apply to may correspond to actors.  However, UML 
use cases capture behaviour, not activity.
   If a SpecGL use case captures behaviour, how is it formalised and 
tested?.
  If a specGL use case does not capture behaviour - does it capture 
activity instead? Or something else?

  -Andrew

  [1] http://www.w3.org/QA/WG/qawg-issues-html.html#x72
  [2] http://www.w3.org/QA/WG/2002/07/qaframe-spec-0722.html
Received on Monday, 29 July 2002 11:27:37 GMT

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