diff --git a/library/src/test/resources/ubl-conv-ubl-output-factur-x.xml b/library/src/test/resources/ubl-conv-ubl-output-factur-x.xml
index 269fbae7..f9daed6d 100644
--- a/library/src/test/resources/ubl-conv-ubl-output-factur-x.xml
+++ b/library/src/test/resources/ubl-conv-ubl-output-factur-x.xml
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<Invoice xmlns:cac="urn:oasis:names:specification:ubl:schema:xsd:CommonAggregateComponents-2"
+<Invoice xmlns="urn:oasis:names:specification:ubl:schema:xsd:Invoice-2" xmlns:cac="urn:oasis:names:specification:ubl:schema:xsd:CommonAggregateComponents-2"
          xmlns:cbc="urn:oasis:names:specification:ubl:schema:xsd:CommonBasicComponents-2"
          xmlns:cec="urn:oasis:names:specification:ubl:schema:xsd:CommonExtensionComponents-2">
   <cbc:CustomizationID>urn:cen.eu:en16931:2017#compliant#urn:fdc:peppol.eu:2017:poacc:billing:3.0</cbc:CustomizationID>