Implemented undocumented 'deleteMessage' method (#602)

* Implemented `Bot.delete_message()` and `Message.delete()` methods

* Added tests for `Bot.delete_message()` and `Messsage.delete()`

* Added myself to `AUTHORS.rst`

* Using `assertRaisesRegexp` instead of `assertRaisesRegex` in tests

Now tests can run on Python 2.7 without raising 'AttributeError'

* Fix docstring

Added a warning to the docstring describing that this method is undocumented and not guaranteed to work

AUTHORS.rst

@@ -24,6 +24,7 @@ The following wonderful people contributed directly or indirectly to this projec
 - `Eli Gao <https://github.com/eligao>`_
 - `ErgoZ Riftbit Vaper <https://github.com/ergoz>`_
 - `Eugene Lisitsky <https://github.com/lisitsky>`_
+- `evgfilim1 <https://github.com/evgfilim1>`_
 - `franciscod <https://github.com/franciscod>`_
 - `Hugo Damer <https://github.com/HakimusGIT>`_
 - `Jacob Bom <https://github.com/bomjacob>`_

telegram/bot.py

@@ -241,6 +241,34 @@ class Bot(TelegramObject):
 
         return url, data
 
+    @log
+    @message
+    def delete_message(self, chat_id, message_id):
+        """Use this method to delete messages which were sent not later than 48 hours ago.
+
+        Args:
+            chat_id (str): Unique identifier for the target chat or
+                username of the target channel (in the format
+                @channelusername).
+            message_id (int): Unique message identifier.
+
+        Note:
+            This method is not documented, so it's not guaranteed to work. Also, its behaviour can
+            be changed at any time.
+
+        Returns:
+            bool: On success, `True` is returned.
+
+        Raises:
+            :class:`telegram.TelegramError`
+
+        """
+        url = '{0}/deleteMessage'.format(self.base_url)
+
+        data = {'chat_id': chat_id, 'message_id': message_id}
+
+        return url, data
+
     @log
     @message
     def forward_message(self,
@@ -1739,6 +1767,7 @@ class Bot(TelegramObject):
     # camelCase aliases
     getMe = get_me
     sendMessage = send_message
+    deleteMessage = delete_message
     forwardMessage = forward_message
     sendPhoto = send_photo
     sendAudio = send_audio

telegram/message.py

@@ -540,6 +540,25 @@ class Message(TelegramObject):
         return self.bot.edit_message_reply_markup(
             chat_id=self.chat_id, message_id=self.message_id, *args, **kwargs)
 
+    def delete(self, *args, **kwargs):
+        """
+        Shortcut for
+
+            >>> bot.delete_message(chat_id=message.chat_id,
+            ...                   message_id=message.message_id,
+            ...                   *args, **kwargs)
+
+        Note:
+            This method is not documented, so it's not guaranteed to work. Also, its behaviour can
+            be changed at any time.
+
+        Returns:
+            bool: On success, `True` is returned.
+
+        """
+        return self.bot.delete_message(
+            chat_id=self.chat_id, message_id=self.message_id, *args, **kwargs)
+
     def parse_entity(self, entity):
         """
         Returns the text from a given :class:`telegram.MessageEntity`.

tests/test_bot.py

@@ -82,6 +82,25 @@ class BotTest(BaseTest, unittest.TestCase):
         self.assertTrue(self.is_json(message.to_json()))
         self.assertEqual(message.text, u'Моё судно на воздушной подушке полно угрей')
 
+    @flaky(3, 1)
+    @timeout(10)
+    def test_deleteMessage(self):
+        message = self._bot.send_message(
+            chat_id=self._chat_id, text='This message will be deleted')
+
+        self.assertTrue(
+            self._bot.delete_message(
+                chat_id=self._chat_id, message_id=message.message_id))
+
+    @flaky(3, 1)
+    @timeout(10)
+    def test_deleteMessage_old_message(self):
+        with self.assertRaisesRegexp(telegram.TelegramError, "can't be deleted"):
+            # NOTE: This behaviour can be changed in future because `deleteMessage` method is not
+            # documented in Bot API reference now.
+            # Considering that the first message is old enough
+            self._bot.delete_message(chat_id=self._chat_id, message_id=1)
+
     @flaky(3, 1)
     @timeout(10)
     def testGetUpdates(self):

tests/test_message.py

@@ -136,6 +136,26 @@ class MessageTest(BaseTest, unittest.TestCase):
         self.assertTrue(self.is_json(message.to_json()))
         self.assertEqual(message.text, 'Testing class method')
 
+    @flaky(3, 1)
+    def test_delete1(self):
+        """Test for Message.delete"""
+        message = self._bot.send_message(
+            chat_id=self._chat_id, text='This message will be deleted')
+
+        self.assertTrue(message.delete())
+
+    @flaky(3, 1)
+    def test_delete2(self):
+        """Another test for Message.delete"""
+        message = self._bot.send_message(
+            chat_id=self._chat_id,
+            text='This ^ message will not be deleted',
+            reply_to_message_id=1)
+
+        with self.assertRaisesRegexp(telegram.TelegramError, "can't be deleted"):
+            # NOTE: This behaviour can be changed in future. See `tests/test_bot.py` for more info
+            message.reply_to_message.delete()
+
 
 if __name__ == '__main__':
     unittest.main()