{
  "endpoint": "issueInvoice",
  "description": "Lager-Kennungen ohne Schraegstrich und nicht nur Punkte",
  "request": {
    "idempotencyKey": "ex-18",
    "priceMode": "gross",
    "serviceStart": "2026-10-01",
    "stockLocationId": "..",
    "items": [
      {
        "description": "Roggenbrot",
        "quantity": 1,
        "unitPriceCents": 450,
        "vatRate": 10,
        "articleId": "a/b"
      }
    ]
  },
  "expected": {
    "ok": false,
    "code": "validation",
    "fields": [
      "stockLocationId",
      "items[0].articleId"
    ]
  }
}