UBL 2 Invoice Calculation Model Draft 1 Suggested Rules

[Stephen Green <stephengreenubl@gmail.com>]

Here are draft rules which are behind my lastest draft of test assertions
for UBL 2.0 Invoice Calculation Model (draft1). Comments, objections, etc
welcome. Maybe these, once broadly agreed (or at least no longer
receiving strong objections with alternative rules) can go to the UBL wiki
as an example of a calculation model.

{ID schema "U20ICMDraft1Rule#..." stands for "UBL 2 Invoice
Calculation Model Draft 1 Rule #..."}

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U20ICMDraft1Rule#1:

"To be a conforming UBL 2 invoice the document must be valid according
to a standard UBL 2 Invoice schema."

U20ICMDraft1Rule#2:

"The document level line extension total should be the sum of all line
extension amounts at line level."

U20ICMDraft1Rule#3:

"The 'TaxExclusiveAmount' in the invoice 'LegalMonetaryTotal' should
be equal to the sum of the 'LineExtensionAmount's in all of the
invoice lines plus the sum of the invoice 'AllowanceCharge' charges
minus the sum of the invoice 'AllowanceCharge' allowances."

U20ICMDraft1Rule#4:

"Provided there is no Prepayment, the 'AllowanceTotalAmount' in the
invoice 'LegalMonetaryTotal' should be equal to the the sum of the
invoice 'AllowanceCharge' allowances."

U20ICMDraft1Rule#5:

"Provided there is no Prepayment, the 'ChargeTotalAmount' in the
invoice 'LegalMonetaryTotal' should be equal to the the sum of the
invoice 'AllowanceCharge' charges."

U20ICMDraft1Rule#6:

"Provided there is no Prepayment, in the invoice 'LegalMonetaryTotal'
the 'LineExtensionAmount' should be equal to the 'TaxExclusiveAmount'
plus any 'AllowanceTotalAmount' minus any 'ChargeTotalAmount'."

U20ICMDraft1Rule#7:

"The 'PayableAmount' in the invoice 'LegalMonetaryTotal' should be
equal to the TaxExclusiveAmount (in the invoice 'LegalMonetaryTotal')
plus the sum of the invoice total tax amounts (at invoice document
level)."

U20ICMDraft1Rule#8:

"The sum of document level tax total amounts should equal the sum of
all document level subtotal tax amounts."

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The test assertions which use these rules and interpret them as XPaths
against the UBL 2.0 Invoice are
publicly posted at
http://www.oasis-open.org/committees/document.php?document_id=34533&wg_abbrev=tag

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Stephen D Green