def test_valid_format_returns_proper_chat_name(self):
     result = get_chat_from_file_name("some_file_20150404_234536.txt")
     self.assertEqual('some_file', result)
 def test_invalid_format_returns_none(self):
     result = get_chat_from_file_name("some_file_20150404_234df.txt")
     self.assertIsNone(result)