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

appengine/findit/model/test/versioned_config_test.py

Index: appengine/findit/model/test/versioned_config_test.py
diff --git a/appengine/findit/model/test/versioned_config_test.py b/appengine/findit/model/test/versioned_config_test.py
new file mode 100644
index 0000000000000000000000000000000000000000..a1d2b268a91a642f0f917552c6b3644b81731c65
--- /dev/null
+++ b/appengine/findit/model/test/versioned_config_test.py
@@ -0,0 +1,53 @@
+# 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.ext import ndb
+
+from testing_utils import testing
+
+from model.versioned_config import VersionedConfig
+
+
+class _Config(VersionedConfig):
+  a = ndb.IntegerProperty(indexed=False, default=0)
+
+
+class VersionedConfigTest(testing.AppengineTestCase):
+  def _CreateFirstVersion(self):
+    config = _Config.Get()
+    config.Update(a=1)
+
+  def testGetWhenNoConfigCreatedYet(self):
+    config = _Config.Get()
+    self.assertIsNotNone(config)
+    self.assertEqual(0, config.a)
+
+  def testNonAdminCanNotUpdate(self):
+    config = _Config.Get()
+    with self.assertRaises(Exception):
+      config.Update()
+
+  def testUpdateWhenChanged(self):
+    self.mock_current_user(user_email='test@chromium.org', is_admin=True)
+    self._CreateFirstVersion()
+    config = _Config.Get()
+    self.assertIsNotNone(config)
+    self.assertTrue(config.Update(a=2))
+
+    config = _Config.Get()
+    self.assertIsNotNone(config)
+    self.assertEqual(2, config.version)
+    self.assertEqual(2, config.a)
+
+  def testNotUpdateWhenNotChanged(self):
+    self.mock_current_user(user_email='test@chromium.org', is_admin=True)
+    self._CreateFirstVersion()
+    config = _Config.Get()
+    self.assertIsNotNone(config)
+    self.assertFalse(config.Update(a=1))
+
+    config = _Config.Get()
+    self.assertIsNotNone(config)
+    self.assertEqual(1, config.version)
+    self.assertEqual(1, config.a)