Fixing flaky datastore queries in regression tests.

Using an ancestor in queries to ensure consistency.

See googleapis#562 for context.

gcloud/datastore/key.py

@@ -155,15 +155,18 @@ def _clone(self):
         """Duplicates the Key.
 
         Most attributes are simple types, so don't require copying. Other
-        attributes like ``parent`` are long-lived and so we re-use them rather
-        than creating copies.
+        attributes like ``parent`` are long-lived and so we re-use them.
 
         :rtype: :class:`gcloud.datastore.key.Key`
         :returns: A new ``Key`` instance with the same data as the current one.
         """
-        return self.__class__(*self.flat_path, parent=self.parent,
-                              dataset_id=self.dataset_id,
-                              namespace=self.namespace)
+        cloned_self = self.__class__(*self.flat_path,
+                                     dataset_id=self.dataset_id,
+                                     namespace=self.namespace)
+        # If the current parent has already been set, we re-use
+        # the same instance
+        cloned_self._parent = self._parent
+        return cloned_self
 
     def completed_key(self, id_or_name):
         """Creates new key from existing partial key by adding final ID/name.

gcloud/datastore/test_key.py

@@ -152,6 +152,25 @@ def test__clone(self):
         self.assertEqual(clone.kind, _KIND)
         self.assertEqual(clone.path, _PATH)
 
+    def test__clone_with_parent(self):
+        _DATASET = 'DATASET-ALT'
+        _NAMESPACE = 'NAMESPACE'
+        _KIND1 = 'PARENT'
+        _KIND2 = 'KIND'
+        _ID1 = 1234
+        _ID2 = 2345
+        _PATH = [{'kind': _KIND1, 'id': _ID1}, {'kind': _KIND2, 'id': _ID2}]
+
+        parent = self._makeOne(_KIND1, _ID1, namespace=_NAMESPACE,
+                               dataset_id=_DATASET)
+        key = self._makeOne(_KIND2, _ID2, parent=parent)
+        self.assertTrue(key.parent is parent)
+        clone = key._clone()
+        self.assertTrue(clone.parent is key.parent)
+        self.assertEqual(clone.dataset_id, _DATASET)
+        self.assertEqual(clone.namespace, _NAMESPACE)
+        self.assertEqual(clone.path, _PATH)
+
     def test_completed_key_on_partial_w_id(self):
         key = self._makeOne('KIND', dataset_id=self._DEFAULT_DATASET)
         _ID = 1234

regression/datastore.py

@@ -55,6 +55,8 @@ def test_allocate_ids(self):
 
 class TestDatastoreSave(TestDatastore):
 
+    PARENT = datastore.Key('Blog', 'PizzaMan')
+
     def _get_post(self, id_or_name=None, post_content=None):
         post_content = post_content or {
             'title': u'How to make the perfect pizza in your grill',
@@ -66,7 +68,10 @@ def _get_post(self, id_or_name=None, post_content=None):
             'rating': 5.0,
         }
         # Create an entity with the given content.
-        entity = datastore.Entity(key=datastore.Key('Post'))
+        # NOTE: Using a parent to ensure consistency for query
+        #       in `test_empty_kind`.
+        key = datastore.Key('Post', parent=self.PARENT)
+        entity = datastore.Entity(key=key)
         entity.update(post_content)
 
         # Update the entity key.
@@ -77,8 +82,7 @@ def _get_post(self, id_or_name=None, post_content=None):
 
     def _generic_test_post(self, name=None, key_id=None):
         entity = self._get_post(id_or_name=(name or key_id))
-        with datastore.Transaction():
-            datastore.put([entity])
+        datastore.put([entity])
 
         # Register entity to be deleted.
         self.case_entities_to_delete.append(entity)
@@ -135,23 +139,26 @@ def test_save_multiple(self):
 
     def test_empty_kind(self):
         query = datastore.Query(kind='Post')
+        query.ancestor = self.PARENT
         posts = list(query.fetch(limit=2))
         self.assertEqual(posts, [])
 
 
 class TestDatastoreSaveKeys(TestDatastore):
 
     def test_save_key_self_reference(self):
-        key = datastore.Key('Person', 'name')
+        parent_key = datastore.Key('Residence', 'NewYork')
+        key = datastore.Key('Person', 'name', parent=parent_key)
         entity = datastore.Entity(key=key)
         entity['fullName'] = u'Full name'
         entity['linkedTo'] = key  # Self reference.
 
-        with datastore.Transaction():
-            datastore.put([entity])
+        datastore.put([entity])
         self.case_entities_to_delete.append(entity)
 
         query = datastore.Query(kind='Person')
+        # Adding ancestor to ensure consistency.
+        query.ancestor = parent_key
         query.add_filter('linkedTo', '=', key)
 
         stored_persons = list(query.fetch(limit=2))