fix: raise an exception if namespace alias is not found in namespace map.

Author: dapper91

pydantic_xml/utils.py

@@ -7,6 +7,8 @@
 import pydantic as pd
 import pydantic_core as pdc
 
+from pydantic_xml import errors
+
 from .element.native import etree
 from .typedefs import Location, NsMap
 
@@ -52,7 +54,13 @@ def from_alias(
         """
 
         if not is_attr or ns is not None:
-            ns = nsmap.get(ns or '') if nsmap else None
+            if ns is None:
+                ns = nsmap.get('') if nsmap else None
+            else:
+                try:
+                    ns = nsmap[ns] if nsmap else None
+                except KeyError:
+                    raise errors.ModelError(f"namespace alias {ns} not declared in nsmap")
 
         return QName(tag=tag, ns=ns)
 

tests/test_misc.py

@@ -320,7 +320,7 @@ class BaseModel(
         BaseXmlModel,
         tag='TestTag',
         ns='TestNamespace',
-        nsmap={'test': 'value'},
+        nsmap={'TestNamespace': 'value'},
         ns_attrs=True,
         search_mode='ordered',
     ):