# Invalid XRechnung missing payment terms

Negative-path handling for invoices where payable amount is positive but settlement timing is absent.

## Fixture metadata

- **Format**: XRechnung
- **Profile**: EN 16931
- **Syntax**: UBL 2.1 Invoice
- **Expected result**: Invalid: missing BT-9 or BT-20
- **Covered BT and rule IDs**: BT-9, BT-20, BT-115, BR-CO-25

## What this tests

Negative-path handling for invoices where payable amount is positive but settlement timing is absent.

A positive amount-due invoice intentionally omitting due date and payment terms.

## Assertions to run

- Validator should fail BR-CO-25 because PayableAmount is positive and both DueDate and PaymentTerms are absent.
- The same invoice should become valid when either BT-9 due date or BT-20 payment terms is added.
- Other core totals are intentionally coherent so the fixture isolates the payment-timing failure.

## Downloads

- [xrechnung-invalid-missing-payment-terms.xml](/resources/test-invoices/xrechnung-invalid-missing-payment-terms.xml): Invalid: missing BT-9 or BT-20
- [test-invoices-manifest.json](/resources/test-invoices/test-invoices-manifest.json): Fixture metadata