YouCompleteMe/python/ycm/tests/mock_utils.py

# Copyright (C) 2017 YouCompleteMe contributors
#
# This file is part of YouCompleteMe.
#
# YouCompleteMe is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# YouCompleteMe is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with YouCompleteMe.  If not, see <http://www.gnu.org/licenses/>.
from __future__ import unicode_literals
from __future__ import print_function
from __future__ import division
from __future__ import absolute_import
# Not installing aliases from python-future; it's unreliable and slow.
from builtins import *  # noqa

import mock
import requests


class FakeResponse( object ):
  """A fake version of a requests response object, just about suitable for
  mocking a server response. Not usually used directly. See
  MockServerResponse* methods"""
  def __init__( self, response, exception ):
    self._json = response
    self._exception = exception
    self.status_code = requests.codes.ok
    self.text = not exception

  def json( self ):
    if self._exception:
      return None
    return self._json


  def raise_for_status( self ):
    if self._exception:
      raise self._exception


class FakeFuture( object ):
  """A fake version of a future response object, just about suitable for
  mocking a server response as generated by PostDataToHandlerAsync.
  Not usually used directly. See MockAsyncServerResponse* methods"""
  def __init__( self, done, response = None, exception = None ):
    self._done = done

    if not done:
      self._result = None
    else:
      self._result = FakeResponse( response, exception )


  def done( self ):
    return self._done


  def result( self ):
    return self._result


def MockAsyncServerResponseDone( response ):
  """Return a fake future object that is complete with the supplied response
  message. Suitable for mocking a response future within a client request. For
  example:

    server_message = {
      'message': 'this message came from the server'
    }

    with patch.object( ycm._message_poll_request,
                       '_response_future',
                       new = MockAsyncServerResponseDone( [] ) ) as mock_future:
      ycm.OnPeriodicTick() # Uses ycm._message_poll_request ...
  """
  return mock.MagicMock( wraps = FakeFuture( True, response ) )


def MockAsyncServerResponseInProgress():
  """Return a fake future object that is incomplete. Suitable for mocking a
  response future within a client request. For example:

    with patch.object( ycm._message_poll_request,
                       '_response_future',
                       new = MockAsyncServerResponseInProgress() ):
      ycm.OnPeriodicTick() # Uses ycm._message_poll_request ...
  """
  return mock.MagicMock( wraps = FakeFuture( False ) )


def MockAsyncServerResponseException( exception ):
  """Return a fake future object that is complete, but raises an exception.
  Suitable for mocking a response future within a client request. For example:

    exception = RuntimeError( 'Check client handles exception' )
    with patch.object( ycm._message_poll_request,
                       '_response_future',
                       new = MockAsyncServerResponseException( exception ) ):
      ycm.OnPeriodicTick() # Uses ycm._message_poll_request ...
  """
  return mock.MagicMock( wraps = FakeFuture( True, None, exception ) )


# TODO: In future, implement MockServerResponse and MockServerResponseException
# for synchronous cases when such test cases are needed.