Fix #273 : Local Structured Property population via .populate(**kwargs) (#274)

* fixes #273
-Return the created model during validation (giving identical functionality to that of StructuredProperty)

* Test for fix #273

* Fix test

Co-authored-by: Carlos de la Guardia <cguardia@yahoo.com>

Author: jwaltgrant

google/cloud/ndb/model.py

@@ -4099,7 +4099,7 @@ def _validate(self, value):
         """
         if isinstance(value, dict):
             # A dict is assumed to be the result of a _to_dict() call.
-            value = self._model_class(**value)
+            return self._model_class(**value)
 
         if not isinstance(value, self._model_class):
             raise exceptions.BadValueError(

tests/unit/test_model.py

@@ -3433,7 +3433,7 @@ class Simple(model.Model):
 
         prop = model.LocalStructuredProperty(Simple, name="ent")
         value = {}
-        assert prop._validate(value) is None
+        assert isinstance(prop._validate(value), Simple)
 
     @staticmethod
     def test__validate_dict_invalid():