[Cuprit-finder] Add MetaDict class.

appengine/findit/libs/test/meta_object_test.py

+# Copyright 2017 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.
+
+import unittest
+
+from libs.meta_object import Element
+from libs.meta_object import MetaDict
+
+
+class ElementTest(unittest.TestCase):
+  """Tests ``Element`` class."""
+
+  def testIsElement(self):
+    """Tests that the ``IsElement`` of ``Element`` object returns True."""
+    self.assertTrue(Element().is_element)
+
+
+class MetaDictTest(unittest.TestCase):
+  """Tests ``MetaDict`` class."""
+
+  def testIsElement(self):
+    """Tests that the ``IsElement`` of ``MetaDict`` object returns True."""
+    self.assertFalse(MetaDict({}).is_element)
+
+  def testMetaDictGetAndSetItem(self):
+    """Tests "get" and "set" item behavior of ``MetaDict``."""
+    d = {'a': 1, 'b': 2, 'c': 3}
+    meta_dict = MetaDict(d)
+    self.assertEqual(meta_dict['a'], d['a'])
+    self.assertEqual(meta_dict.get('b'), d.get('b'))
+    meta_dict['a'] = 9
+    d['a'] = 9
+    self.assertEqual(meta_dict['a'], d['a'])
+
+  def testMetaDictIterDict(self):
+    """Tests iterating ``MetaDict``."""
+    d = {'a': 1, 'b': 2, 'c': 3}
+    meta_dict = MetaDict(d)
+    self.assertListEqual(list(key for key in meta_dict), list(key for key in d))
+    self.assertListEqual(list(meta_dict.iteritems()), list(d.iteritems()))
+    self.assertListEqual(list(meta_dict.itervalues()), list(d.itervalues()))
+    self.assertListEqual(meta_dict.keys(), d.keys())
+    self.assertListEqual(meta_dict.values(), d.values())
+    self.assertEqual(MetaDict(d), MetaDict(d))