BR-O-09
The VAT category tax amount (BT-117) in a VAT breakdown (BG-23) where the VAT category code (BT-118) is "Not subject to VAT" shall be 0 (zero).
What the rule checks
As the rule set's publisher wrote it. The rule runs on every element the context matches, and fails where the test is false; the validator reports the line of that element.
/*/cac:TaxTotal/cac:TaxSubtotal/cac:TaxCategory[normalize-space(cbc:ID) = 'O'][cac:TaxScheme/normalize-space(upper-case(cbc:ID))='VAT']
xs:decimal(../cbc:TaxAmount) = 0
Checked with EN 16931 Invoice (UBL), EN 16931 Credit Note (UBL), Croatia eRačun Invoice (UBL), Croatia eRačun Credit Note (UBL)
//rsm:SupplyChainTradeTransaction/ram:ApplicableHeaderTradeSettlement/ram:ApplicableTradeTax[ram:CategoryCode = 'O'][upper-case(ram:TypeCode) = 'VAT']
ram:CalculatedAmount = 0
Checked with EN 16931 Invoice (CII)
//rsm:SupplyChainTradeTransaction/ram:ApplicableHeaderTradeSettlement/ram:ApplicableTradeTax[ram:CategoryCode = 'O']
ram:CalculatedAmount = 0
Checked with France Factur-X BASIC WL, Factur-X / ZUGFeRD BASIC WL