diff --git a/test/data/invoice-pl-pl.json b/test/data/invoice-pl-pl.json
index 3447285..3c4c10c 100644
--- a/test/data/invoice-pl-pl.json
+++ b/test/data/invoice-pl-pl.json
@@ -11,7 +11,8 @@
 	"doc": {
 		"$schema": "https://gobl.org/draft-0/bill/invoice",
 		"type": "standard",
-		"code": "SAMPLE-001",
+		"series": "SAMPLE",
+		"code": "001",
 		"issue_date": "2023-12-20",
 		"currency": "PLN",
 		"supplier": {