[Cuprit-finder] Add MetaDict class.

appengine/findit/libs/test/meta_dict_serializer_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_dict_serializer import ElementSerializer
+from libs.meta_dict_serializer import GetSerializer
+from libs.meta_dict_serializer import MetaDictSerializer
+from libs.meta_object import Element
+from libs.meta_object import MetaDict
+
+
+class ElementSerializerTest(unittest.TestCase):
+  """Tests that ``ElementSerializer`` works as expected."""
+
+  def testToList(self):
+    """Tests ``ToList`` method."""
+    element = Element()
+    element_serializer = ElementSerializer()
+    self.assertListEqual(element_serializer.ToList(element), [element])
+    self.assertListEqual(element_serializer.ToList(None), [None])
+
+  def testToListRaisesException(self):
+    """Tests that ``ToList`` raises exception when input is not ``Element``."""
+    element_serializer = ElementSerializer()
+    self.assertRaisesRegexp(
+        Exception,
+        'ElementSerializer can only serialize Element object.',
+        element_serializer.ToList, MetaDict({}))
+
+  def testFromList(self):
+    """Tests ``FromList`` method."""
+    element = Element()
+    element_serializer = ElementSerializer()
+    self.assertEqual(element_serializer.FromList([element], lambda x: x),
+                     element)
+
+
+class MockedElement(Element):
+
+  def __init__(self, value):
+    self.value = value
+
+  def __eq__(self, other):
+    return self.value == other.value
+
+  def __ne__(self, other):
+    return not self.__eq__(other)
+
+
+class MockedMetaDict(MetaDict):  # pragma: no cover
+
+  def __eq__(self, other):
+    if not len(self._value) == len(other._value):
+      return False
+
+    for key, meta_object in self.iteritems():
+      if meta_object != other.get(key):
+        return False
+
+    return True
+
+  def __ne__(self, other):
+    return not self.__eq__(other)
+
+
+class MetaDictSerializerTest(unittest.TestCase):
+  """Tests that ``MetaDictSerializer`` works as expected."""
+
+  def testToList(self):
+    """Tests ``ToList`` method."""
+    meta_dict = MockedMetaDict(
+        {'a': MockedMetaDict({'b': MockedElement(1), 'c': MockedElement(3)}),
+         'd': MockedElement(2)})
+    serializer = GetSerializer(meta_dict)
+    expected_element_list = [MockedElement(1), MockedElement(3),
+                             MockedElement(2)]
+    element_list = serializer.ToList(meta_dict)
+    for element, expected_element in zip(element_list, expected_element_list):
+      self.assertEqual(element.value, expected_element.value)
+
+  def testFromList(self):
+    """Tests ``FromList`` method."""
+    meta_dict = MockedMetaDict(
+        {'a': MockedMetaDict({'b': MockedElement(1), 'c': MockedElement(3)}),
+         'd': MockedElement(2), 'e': MockedElement(0)})
+    serializer = GetSerializer(meta_dict)
+    element_list = [MockedElement(1), MockedElement(3),
+                    MockedElement(2), MockedElement(0)]
+    self.assertTrue(meta_dict == serializer.FromList(
+        element_list, meta_constructor=MockedMetaDict))
+    self.assertDictEqual(serializer.FromList(element_list),
+                         {'a': {'b': MockedElement(1), 'c': MockedElement(3)},
+                          'd': MockedElement(2), 'e': MockedElement(0)})
+
+  def testFromListRaisesException(self):
+    """Tests ``FromList`` raises exception when lengths mismatch."""
+    meta_dict = MetaDict(
+        {'a': MetaDict({'b': MockedElement(1), 'c': MockedElement(3)}),
+         'd': MockedElement(2), 'e': MockedElement(0)})
+    serializer = GetSerializer(meta_dict)
+    self.assertRaisesRegexp(
+        Exception,
+        'The element list should have the same length as serializer',
+        serializer.FromList, [], MockedMetaDict)