new_contents: 
  import unittest
  
  import changeling.api
  import changeling.fakes
  
  
  class TestChangeAPI(unittest.TestCase):
      def setUp(self):
          self.fake_storage = changeling.fakes.FakeStorage([])
          self.api = changeling.api.ChangeAPI(self.fake_storage)
  
      def test_list_zero_changes(self):
          self.assertEqual([], list(self.api.list()))
  
subject: Add integration tests for ChangeAPI