Description

1. The tax invoice template from KART-VN only allows one tax rate per invoice.
2. Therefore, we need to ensure that all service charges per tax invoice shall carry the same VAT tax rate.

Objectives

1. Return a state to the FO to indicate whether a KART-VN invoice is printable on dot-matrix. Add a constraint to disallow printing when invoice contains service charges of multiple VAT rates.
2. Gracefully return a http response with the right HTTP code when a request is made to generate invoice PDF for KART-VN with the constraint described in the description.

Estimation

4 hours, include development, developer testing, unit test development (if applicable) and peer test/review.