Refined error message.

python/message.c

@@ -255,8 +255,8 @@ static bool PyUpb_CMessage_LookupName(PyUpb_CMessage* self, PyObject* py_name,
   if (!upb_msgdef_lookupname(msgdef, name, size, f, o)) {
     if (exc_type) {
       PyErr_Format(exc_type,
-                   "Protocol message %s has no field or oneof named %s.",
-                   upb_msgdef_fullname(msgdef), name);
+                   "Protocol message %s has no \"%s\" field.",
+                   upb_msgdef_name(msgdef), name);
     }
     return false;
   }

python/pb_unit_tests/reflection_test_wrapper.py

@@ -39,7 +39,6 @@ reflection_test.SerializationTest.testCanonicalSerializationOrder.__unittest_exp
 reflection_test.SerializationTest.testCanonicalSerializationOrderSameAsCpp.__unittest_expecting_failure__ = True
 reflection_test.SerializationTest.testFieldDataDescriptor.__unittest_expecting_failure__ = True
 reflection_test.SerializationTest.testFieldProperties.__unittest_expecting_failure__ = True
-reflection_test.SerializationTest.testInitArgsUnknownFieldName.__unittest_expecting_failure__ = True
 
 if __name__ == '__main__':
   unittest.main(module=reflection_test, verbosity=2)