[Findit] Add a model to provide versioning and also a verioned config model.

appengine/findit/model/test/versioned_model_test.py

Index: appengine/findit/model/test/versioned_model_test.py
diff --git a/appengine/findit/model/test/versioned_model_test.py b/appengine/findit/model/test/versioned_model_test.py
new file mode 100644
index 0000000000000000000000000000000000000000..4aeaa8bc5dd15cddccbc8c19f4f5c4ba526ef52d
--- /dev/null
+++ b/appengine/findit/model/test/versioned_model_test.py
@@ -0,0 +1,96 @@
+# Copyright 2015 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+from google.appengine.api import datastore_errors
+from google.appengine.ext import ndb
+
+from testing_utils import testing
+
+from model.versioned_model import VersionedModel
+
+
+class _Entity(VersionedModel):
+  value = ndb.IntegerProperty(indexed=False)
+
+
+class VersionedModelTest(testing.AppengineTestCase):
+  def testGetRootModel(self):
+    root_model_class = _Entity._GetRootModel()
+    self.assertEqual('_EntityRoot', root_model_class._get_kind())
+    self.assertTrue(issubclass(root_model_class, ndb.Model))
+    self.assertEqual(3, root_model_class(current=3).current)
+
+  def testGetMostRecentVersionWhenNoData(self):
+    entity = _Entity.GetMostRecentVersion()
+    self.assertIsNone(entity)
+
+  def testGetMostRecentVersionWhenDataExists(self):
+    root_key = ndb.Key('_EntityRoot', 1)
+    _Entity._GetRootModel()(key=root_key, current=2).put()
+    _Entity(key=ndb.Key('_Entity', 1, parent=root_key), value=1).put()
+    _Entity(key=ndb.Key('_Entity', 2, parent=root_key), value=2).put()
+
+    entity = _Entity.GetMostRecentVersion()
+    self.assertEqual(2, entity.version)
+    self.assertEqual(2, entity.value)
+
+  def testSaveNewVersion(self):
+    entity = _Entity()
+    entity.value = 1
+    key = entity.Save()
+
+    expected_key = ndb.Key('_EntityRoot', 1, '_Entity', 1)
+    self.assertEqual(expected_key, key)
+
+    entity = _Entity.GetMostRecentVersion()
+    self.assertEqual(1, entity.version)
+    self.assertEqual(1, entity.value)
+
+  def testSaveNewVersionAlreadyExist(self):
+    original_ndb_transaction = ndb.transaction
+
+    def MockNdbTransaction(func, **options):
+      _Entity(key=ndb.Key('_EntityRoot', 1, '_Entity', 1), value=1).put()
+      _Entity(key=ndb.Key('_EntityRoot', 1, '_Entity', 2), value=2).put()
+      return original_ndb_transaction(func, **options)
+    self.mock(ndb, 'transaction', MockNdbTransaction)
+
+    entity = _Entity()
+    key = entity.Save()
+    expected_key = ndb.Key('_EntityRoot', 1, '_Entity', 3)
+    self.assertEqual(expected_key, key)
+
+  def testLikelyTransactionFailure(self):
+    original_ndb_transaction = ndb.transaction
+
+    calls = []
+    def MockNdbTransaction(func, **options):
+      if len(calls) < 1:
+        calls.append(1)
+        raise datastore_errors.Timeout()
+      return original_ndb_transaction(func, **options)
+    self.mock(ndb, 'transaction', MockNdbTransaction)
+
+    entity = _Entity()
+    key = entity.Save()
+    expected_key = ndb.Key('_EntityRoot', 1, '_Entity', 1)
+    self.assertEqual(expected_key, key)
+    self.assertEqual([1], calls)
+
+  def testTransactionFailure(self):
+    original_ndb_transaction = ndb.transaction
+
+    calls = []
+    def MockNdbTransaction(func, **options):
+      if len(calls) < 1:
+        calls.append(1)
+        raise datastore_errors.BadRequestError()
+      return original_ndb_transaction(func, **options)
+    self.mock(ndb, 'transaction', MockNdbTransaction)
+
+    entity = _Entity()
+    key = entity.Save()
+    expected_key = ndb.Key('_EntityRoot', 1, '_Entity', 1)
+    self.assertEqual(expected_key, key)
+    self.assertEqual([1], calls)