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Subject: Re: [ubl-comment] Ammendment Re: Suggestion for a basis for subsetprofile conformance clauses


"conformance type 1: (as I wrote previously) "
 
of course in my second conformance type that should just read
 
"conformance type 2:"

 
----
Stephen D Green



On 2 August 2011 12:51, Stephen D Green <stephengreenubl@gmail.com> wrote:
Third time lucky...  I'm still getting to grips with this. Sorry
for my slowness to understand it all.
 
Now I think some more I reckon there can be two main
conformance levels/types (or three if you add one combining
the other two) for a given subset.
 
conformance type 1: (as I wrote previously)
the sender
can send every BIE in a conformance (sub)set of the subset
the receiver
can receive a document with every BIE in the subset
 
but then there is the other type, to which I think you allude
 
conformance type 1: (as I wrote previously)
the sender (has a mode of operation in which it ...)
can send a document with no BIEs which are not in a conformance (sub)set of the subset
the receiver
can receive a document with every BIE in the subset
and
can fail to receive (reject) any document with BIEs which are not in a conformance (sub)set of the subset
 
The second can make the schema central to conformance tests.
 
The second is more valuable to receiving systems but may be less testable (not every doc can be tested).
 
I guess both have pros and cons.
 
The first is to my thinking more akin with Postel's law putting less onus on senders. Both are valid though.
 
Best regards
----
Stephen D Green



On 2 August 2011 09:27, Stephen D Green <stephengreenubl@gmail.com> wrote:
Hi Jon
 
Reading through your question again, I may not have answered it.
 
Are you asking for elaboration on the actual 'predicates' in the test assertions?
In other words, the actual logic of the suggested profile spec statements?
 
I guess they are aimed more at a sending system than at the document sent.
That is the key to understanding how they differ from (subset) schema validity.
The schema constrains the document but these statements (and test assertions
based on the statements) go ufrther by stating that a sending system MUST
be able to send X, Y and Z in a document. That is not to say a document MUST
contain X, Y and Z. If Z is mandatory in the schema, one document might contain 
Y and Z and another document might contain X and Z. If the system can send
a document with X and Z and it can send a document with Y and Z it conforms.
It it cannot send Y and Z then it doesn't conform to this profile (even though its
documents might all be valid according to the schema). If it sends documents
with X and Y but not Z then there will be a failed test but this cannot always be
relied on for conformance because tests cannot prove it will never send such
a document. This is the weakness of using a schema and validity of documents
alone as a conformance test - you can never test all documents. My suggestion
is to apply conformance testing such that the sending system has to prove that
it can send some set of documents which between them contain all BIEs in a
set. (It is a little more complex in that the subset itself may be a superset of all
the BIEs in the set required for conformance. A conforming system can still
conform, according to a given profile spec, even if it never, say, implements
each and every, Signature BIE, provided these BIEs are not part of the set
which determines conformance. The Signature BIEs might all be there in the
subset schema though.) 
----
Stephen D Green



On 1 August 2011 17:49, Jon Bosak <bosak@pinax.com> wrote:
Hello Stephen,

I like the idea of a basic subset (always have), and I'm happy to have
the benefit of your work on this.

A question about the test assertion approach, however.  I'm having
trouble seeing how these assertions go beyond just saying "you have to
validate against the subset schema, and in addition, these optional UBL
elements are mandatory."  (In which case, of course, you could just
modify the subset schema to that effect.)  Could you help me understand
this?

Jon

Stephen D Green wrote:
I would refine the previous comment to say that the previous receiving system
conformance clause might not have been fully testable (since not every possible
document received will be tested). I could refine this to say that a receivng system
MUST be able to receive a document which contains every element in the subset
and every multiple cardinality element twice or more times in the document.
 I would suggest that continuing along the lines of a conformance test centric subset profile there might be consideration of test assertions for such a
profile, again considering testability of the assertions and the normative
statements from which they are derived.
 Here is an example of a test assertion set for, say, a conformance clause relating to
the invoice document type (there might be a clause for each type to allow
implementations to implement just one or more document types and still
be conformant).
 It is based on an example profile which somehow lists every element (ignoring
attributes for conformance requirements except insofar as they are ever mandatory
for the UBL standard schema validity for that document type)
 e.g.
 Where the profile for the subsets contains statements like this:
...
Statement INV004: A subset sending system which can send a subset invoice MUST be able to send a document valid according to the OASIS standard UBL 2.1 Invoice schema and containing element /in:Invoice/cbc:ID
 Statement INV005: A subset sending system which can send a subset invoice MUST be able to send a document valid according to the OASIS standard UBL 2.1 Invoice schema and containing element /in:Invoice/cbc:CopyIndicator
... one such statement for each element in the subset or a table to the same effect or some other
blanket statement to this effect including reference to an overall schema for the subset
...
 The conformance clause for subset invoice sending systems would require conformance to
all these statements. Another clause for receiving systems might require conformance to
a statement that receiving systes receiving a subset invoice be able to receive one with all
elements in the subset (including multiple occurences where the schema includes multiple
occurences).
 Test assertions could be presented in the form of markup like this
-- here using OASIS (in progress) Test Assertion Markup Language:


<!-- one set of normative statements and corresponding test assertions for every document type in the subset and for each of these sets one corresponding conformance clause for sending systems (for that document type) and one for recieving systems (for that document type) -->
<testAssertionSet xmlns="http://docs.oasis-open.org/ns/tag/taml-201002/" setid="ubl-subset.example.ta-set.1" setname="Invoice Subset">
<common>
...
<!-- need some bindings for prefixes used in the XPath expressions -->
</common>
...
<testAssertion id="ubl-invoice-subset.example.ta.s4">
<!-- the actual nomative source might be a table or might rely on a schema to list all elements in the subset (attributes too but these might be optional) -->
<normativeSource><derivedSourceItem documentId="..." resourceProvenanceId="..." uri="...">A subset sending system which can send a subset invoice MUST be able to send a document valid according to the OASIS standard UBL 2.1 Invoice schema and containing element /in:Invoice/cbc:ID</derivedSourceItem></normativeSource>
<target>subset sending system</target>
<prerequisite>can send a subset document valid according to the OASIS standard UBL 2.1 Invoice schema</prerequisite>
<predicate>can send a document valid according to the OASIS standard UBL 2.1 Invoice schema and containing element /in:Invoice/cbc:ID</predicate>
<prescription level="mandatory"/>
</testAssertion>
<testAssertion id="ubl-invoice-subset.example.ta.s5">
<normativeSource><derivedSourceItem documentId="..." resourceProvenanceId="..." uri="...">...</derivedSourceItem></normativeSource>
<target>subset sending system</target>
<prerequisite>can send a subset document valid according to the OASIS standard UBL 2.1 Invoice schema</prerequisite>
<predicate>can send a document valid according to the OASIS standard UBL 2.1 Invoice schema and containing element /in:Invoice/cbc:CopyIndicator</predicate>
<prescription level="mandatory"/>
</testAssertion>
<testAssertion id="ubl-invoice-subset.example.ta.s6">
<normativeSource><derivedSourceItem documentId="..." resourceProvenanceId="..." uri="...">...</derivedSourceItem></normativeSource>
<target>subset sending system</target>
<prerequisite>can send a subset document valid according to the OASIS standard UBL 2.1 Invoice schema</prerequisite>
<predicate>can send a document valid according to the OASIS standard UBL 2.1 Invoice schema and containing element /in:Invoice/cbc:UUID</predicate>
<prescription level="mandatory"/>
</testAssertion>

<!-- one normative statement and corresponding test assertion for every element in the subset for that document type -->
...

<testAssertion id="ubl-invoice-subset.example.ta.r1">
<normativeSource><derivedSourceItem documentId="..." resourceProvenanceId="..." uri="...">...</derivedSourceItem></normativeSource>
<target>subset receiving system</target>
<prerequisite>can receive a subset document valid according to the OASIS standard UBL 2.1 Invoice schema</prerequisite>
<predicate>can receive a document valid according to the OASIS standard UBL 2.1 Invoice schema and containing every single-occurence element in that subset once and multiple-occurence element in that document twice or more</predicate>
<prescription level="mandatory"/>
</testAssertion>
...

</testAssertionSet>

 Best regards
 ----
Stephen D Green



On 30 July 2011 18:40, Stephen D Green <stephengreenubl@gmail.com <mailto:stephengreenubl@gmail.com>> wrote:

   Suggestion for a basis for subset profile conformance clauses
             In the UBL 1.0 Small Business Subset were clauses which
   I found later to be very difficult to test precisely and this
   might make conformance testing and conformance claims
   problematic. The introduction of conformance clauses in
   recent standard specifications is to aid interoperability and
   promote adoption through the clarification of what it means
   for an implementation to conform to a standard specification.
        To promote adoption of subsets for the OASIS Universal
   Business Language it is important to include a conformance
   clause of set of clauses and I would suggest that a subset
   conformance clause should target more than just the UBL
   documents (Invoice, Order, etc) themselves but also there
   should be a conformance clause for a sending system, one
   for a receiving system instead of or in addition to the clause
   for conformance of the documents themselves. I would like
   to suggest as a basis for the clause for the conformance
   target of sending system conformance to a set of statements
   which amount to the sending system being able to send a
   certain set of BIEs in a given document, as defined by the
   subset schema for that document. I would suggest that a
   basis for a clause for the target of a receiving system would     be a conformance clause requiring that the system MUST
   NOT reject a document merely because of the presence in
   it of any of the BIEs as defined by the subset schema (or
   list of BIEs, e.g. given as a set of XPath expressions).
        As a simplistic example, if a subset contains BIEs X,Y,Z of
   which Y and Z are mandatory and X is optional, there could
   be a set of specification requirements to the effect that the
   sender system MUST be able to send all BIEs X, Y and Z
   in sending that particular document (even though only Y
   and Z are mandatory in any given document of that type).
   A conformance clause for the target of the sending system
   would mandate these particular statements as necessary
   for the conformance of that system. A set of statements that
   target the receiving system would require that the system
   MUST NOT reject a document of that type merely because
   it contains BIE X or Y or Z. A conformance clause for the
   receiving system would make the statements mandatory
   for conformance by such a system. There would be a set of     statements for each conformance target that the documents
   of that type MUST contain BIEs Y and Z because these are
   mandatory.
        Such conformance clauses and this focus on testability may
   help to promote adoption of any given subset and contribute
   to successful adoption and interoperable implementations.
             Best regards
        ----
   Stephen D Green







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