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Re: What is a subject of a test?

From: Shadi Abou-Zahra <shadi@w3.org>
Date: Wed, 30 Mar 2005 22:38:19 +0200
To: "'Johannes Koch'" <johannes.koch@fit.fraunhofer.de>, <public-wai-ert@w3.org>
Message-ID: <006101c53568$69084df0$4502010a@K2>

Hi Johannes,

I'm thinking out loud:

Missing alt texts could be addressed by something like "//img!@alt" (not
sure if that is correct XPath). In such a case, it is probably better to
have one assertion per test case (because such a generic pointer
supports some sense of persistency).

However, if the error is a "bad" alt text, then we would probably need
to regard the value of the alt attribute too (e.g. "//img@alt='stupid
text'"). There are occasions when such an expression could match more
than one occurrence, (for example if the evaluation tool can be
configured to alert when it encounters the string 'stupid text' as an
alt text) but in end effect we may be generating more than one assertion
for a single test case.

Finally, if we can not use such XPath-type expressions (for example if
the page is not well formed [enough]), then the Subject probably has the
be the URL of the page (i.e. we can not differentiate the location for
the different instances).

So it seems that ideally the Subject is [something like] an XPath if the
document is well formed, or a simple URL as a [compatible] fallback. The
number of assertions which are generated depends on the test itself
(because that could also effect confidence, error message, etc).

What do you think?

Regards,
  Shadi


-----Original Message-----
From: public-wai-ert-request@w3.org On Behalf Of Johannes Koch
Sent: Wednesday, March 30, 2005 16:54
To: public-wai-ert@w3.org
Subject: What is a subject of a test?



When implementing EARL I asked myself "what is the subject of a test" 
and "how many asertions"?

Example:
HTML test document with two images.
Test: look for alt attributes.
Result: None has alt attribute.

Version 1:
One Assertion, one subject (URL of document), one testCase (alt 
attribute test), one result (fail) with two messages (about each of the 
images, including location information)

Version 2:
Two Assertions, each with same subject (URL of document), same testCase,

one message each (including location information)

Version 3:
Two Assertions, different subject (URL of document + xpointer of error 
instance), same testCase, one message each

Comments?
-- 
Johannes Koch - Competence Center BIKA
Fraunhofer Institute for Applied Information Technology (FIT.LIFE)
Schloss Birlinghoven, D-53757 Sankt Augustin, Germany
Phone: +49-2241-142628
Received on Wednesday, 30 March 2005 20:38:15 GMT

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