Bugfix to show correct error message show in case of unknown field in a datatype

Change-Id: I3207b0ba7bf02154381e472dd2ee0496efdb5f20
Related-Bug: 1573139

toscaparser/dataentity.py

@@ -91,7 +91,10 @@ class DataEntity(object):
 
             # check every field
             for name, value in list(self.value.items()):
-                prop_schema = Schema(name, self._find_schema(name))
+                schema_name = self._find_schema(name)
+                if not schema_name:
+                    continue
+                prop_schema = Schema(name, schema_name)
                 # check if field value meets type defined
                 DataEntity.validate_datatype(prop_schema.type, value,
                                              prop_schema.entry_schema,

toscaparser/tests/test_datatypes.py

@@ -477,3 +477,30 @@ class DataTypeTest(TestCase):
         data = DataEntity('tosca.my.datatypes.TestLab', value,
                           DataTypeTest.custom_type_def)
         self.assertIsNotNone(data.validate())
+
+    def test_incorrect_field_in_datatype(self):
+        tpl_snippet = '''
+        tosca_definitions_version: tosca_simple_yaml_1_0
+        topology_template:
+          node_templates:
+            server:
+              type: tosca.nodes.Compute
+
+            webserver:
+              type: tosca.nodes.WebServer
+              properties:
+                admin_credential:
+                  user: username
+                  token: some_pass
+                  some_field: value
+              requirements:
+                - host: server
+        '''
+        tpl = yamlparser.simple_parse(tpl_snippet)
+        err = self.assertRaises(exception.ValidationError, ToscaTemplate,
+                                None, None, None, tpl)
+        self.assertIn(_('The pre-parsed input failed validation with the '
+                        'following error(s): \n\n\tUnknownFieldError: Data '
+                        'value of type "tosca.datatypes.Credential" contains'
+                        ' unknown field "some_field". Refer to the definition'
+                        ' to verify valid values'), err.__str__())