Re: [tag] Re: TAG Proposal on weak predicates

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

Comment/question below

2008/7/12 Durand, Jacques R.
> I suggest we add a
> "Testability" section (~1 page) in our guideline.
> This section would deal with all the fuzziness behind the notion of
> "testability" , which is precisely what a guideline is about, i.e. best
> practices rather than exact science). Because testability is a relative
> concept dependent on what test constraints are assumed, I suspect that our
> guideline might have to consider a few cases:
> (a) the TA writer assumes that it is always possible to derive test case(s)
> from the TA, given the right test environment. In other words, it is assumed
> there is no restriction on the execution of test cases.
> (b) the TA writer works under "testability" constraint, and writes TA with
> these testing constraints in mind.
> I suspect that neither (a) nor (b) is wrong...
>


A TA writer will doubtless have in mind (to a greater
or lesser extent) some expectation of a set of test
constraints (else how will they consider what it means
that their TAs are 'testable'). They will doubtless be
able and likely to form opinions, as they write the
assertions, about how testable the assertions are and
how testable the corresponding spec statements are.
I think there is no disagreement that such thoughts
could be captured and should, when useful, be
captured. What we seem to have a split of opinion on
(interestingly) is *how* those thoughts may or should
be used and associated at all with the corresponding
TA.

A few of us are thinking that the proper place for them
is ultimately in metadata to be associated with test suites/cases. The
'other side of the coin' of this
opinion is that the TA is *not* a proper place for such
opinions because 1) they are opinions (whereas a TA
is otherwise to be a statement of fact following on
from the spec) an 2) including them with the TA risks
diluting the logic of the spec (even if that logic is
already considered by the TA writer to be flawed or
weak in some way).

Against this opinion, on the other side as it were,
what reason would there be for including opinions
about expectations of test constraints and/or
opinions about corresponding testability of a TA
in the TA itself?

-- 
Stephen D. Green

Partner
SystML, http://www.systml.co.uk
Tel: +44 (0) 117 9541606
Associate Director
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http://www.biblegateway.com/passage/?search=matthew+22:37 .. and voice