Message

Tax Category G MUST be used when exemption reason code is VATEX-EU-G

Context
cac:TaxCategory[upper-case(cbc:TaxExemptionReasonCode)='VATEX-EU-G']
Test
normalize-space(cbc:ID)='G'
Usage
/ ubl:Invoice / cac:TaxTotal / cac:TaxSubtotal / cac:TaxCategory / cbc:TaxExemptionReasonCode