Mocking await calls in python 3.5 is a problem

problem.py

async def some_coroutine():
    await async.sleep(10.0)
    await another_coroutine()
    return 'test'


async def another_coroutine():
    pass

problem_test.py

from unittest import TestCase, mock, main
import asyncio

from problem import some_coroutine


class AsyncMock(mock.MagicMock):
    async def __call__(self, *args, **kwargs):
        return super(AsyncMock, self).__call__(*args, **kwargs)

    
class Test(TestCase):

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

    @mock.patch('problem.asyncio.sleep', new_callable=AsyncMock)
    @mock.patch('problem.another_coroutine', new_callable=AsyncMock)
    def test_some_coroutine(self, mock_another_coroutine, sleep):
        async def run_test():
            resp = await some_coroutine()
            
            mock_another_coroutine.assert_called_with()
            sleep.assert_called_with(10.0)
            self.assertEqual(resp, 'test')

        self.loop.run_until_complete(run_test())


if __name__ == '__main__':
    main()