# Invalid XRechnung missing buyer reference

Negative path for the most common XRechnung rejection: an invoice without the buyer reference that public buyers use for routing.

## Fixture metadata

- **Format**: XRechnung
- **Profile**: EN 16931
- **Syntax**: UBL 2.1 Invoice
- **Expected result**: Invalid: missing BT-10 (BR-DE-15)
- **Covered BT and rule IDs**: BT-10, BR-DE-15

## What this tests

Negative path for the most common XRechnung rejection: an invoice without the buyer reference that public buyers use for routing.

The valid basic invoice with the buyer reference (BT-10, Leitweg-ID) intentionally removed.

## Assertions to run

- Validator should fail BR-DE-15 because cbc:BuyerReference (BT-10) is absent.
- The same invoice should become valid when the buyer reference, usually the Leitweg-ID, is added.
- All other content equals the valid basic fixture, so the fixture isolates the buyer reference failure.

## Downloads

- [xrechnung-invalid-missing-buyer-reference.xml](/resources/test-invoices/xrechnung-invalid-missing-buyer-reference.xml): Invalid: missing BT-10 (BR-DE-15)
- [test-invoices-manifest.json](/resources/test-invoices/test-invoices-manifest.json): Fixture metadata