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

From
Rtephen E Hreen
Date
2011-08-07T11:28:38+00:00
ID
CAA0AChXh0MUwzVvbiqA7USpvA8tMbZiugc8-4dC89ngbO=
Thread
Re: [ubl-comment] Ammendment Re: Suggestion for a basis for subsetprofile conformance clauses
If it helps, I thought to call conformance type 1 the 'benchmark'
(it is a sender capabilities minimum requirement for conformance)
and the conformance type 2 the 'ceiling' (it is where the sender

is bound to not send anything which does not conform to a subset
schema (and the subset schema sets the outer bounds of what
can be sent) - in a certain mode (outside of that mode the profile
does not apply but other profiles might such as overall standard

conformance).

I would suggest that these two conformance types - ceiling and
benchmark - could be defined using separate subsets, all within 
one 'subset conformance profile'. One part of the conformance

clause could define the benchmark using one subset (e.g. the
subset I labelled just 'subset' and of the order of UBL 1.0 SBS)
and another part of the clause could define the ceiling using
a separate larger subset (obviously it has to be the same 'size'

or larger, such as the subset schema set I called 'subsetPlus').

It would make sense to me if the proposed basic subset for
UBL 2.1 did in fact use a benchmark like my 'subset' sent
previously but defined using XPaths (e.g. in both a table in

the spec and perhaps test assertions based on that table)
and it would make sense if it also included a ceiling like
the subsetPlus schema set I sent where all BIEs in well
known existing subsets such as OIO were included along

with the previous benchmark subset BIEs too. Then a 
conforming target implementation would ensure it can 
send all BIEs in the 'inner', 'benchmark' and also ensure it
has a mode of use (perhaps indicated using one of the 

purpose made UBL IDs like ProfileID or CustomisationID)
where it does not send anything not valid according to the
ceiling. The ceiling conformance could be tested with a
ceiling subset and there might be a need for test cases 

(perhaps using the XPaths) to test that every possible
benchmark BIE *CAN* be included in any document.   
----

Stephen D Green

On 2 August 2011 14:48, Jon Bosak <> wrote:

Thanks, Stephen.  I'm going to arrange a discussion of this in an

upcoming TC call.

Jon

Stephen D Green 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 < <mailto:>> 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 <

    <mailto:>> 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/

            <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

            <

            <mailto:>

            <mailto:stephengreenubl@gmail.__com

            <mailto:>>> 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