Mocking await calls in python 3.5 is a problem

problem.py

async def some_coroutine():
    await another_coroutine()


async def another_coroutine():
    pass

problem_test.py

from unittest import TestCase, mock, main
import asyncio

from problem import some_coroutine


class Test(TestCase):

    def setUp(self):
        self.loop = asyncio.new_event_loop()
        asyncio.set_event_loop(self.loop)

    @mock.patch('problem.another_coroutine')
    def test_some_coroutine(self, mock_another_coroutine):
        async def run_test():
            await some_coroutine()
            mock_another_coroutine.assert_called_with()

        self.loop.run_until_complete(run_test())


if __name__ == '__main__':
    main()