@mock.patch decorator doesnt work properly with @pytest.mark.asyncio

[sashgorokhov]

Sample test code:

tests.py

from unittest import mock

import pytest
import testmodule


@pytest.mark.asyncio
async def test_async_mock_patch_contextmanager():
    with mock.patch('testmodule.foo') as foo_mock:
        assert testmodule.foo is foo_mock


@pytest.mark.asyncio
@mock.patch('testmodule.foo')
async def test_async_mock_patch_decorator(foo_mock):
    assert testmodule.foo is foo_mock  # FAILS


def test_mock_patch_contextmanager():
    with mock.patch('testmodule.foo') as foo_mock:
        assert testmodule.foo is foo_mock


@mock.patch('testmodule.foo')
def test_mock_patch_decorator(foo_mock):
    assert testmodule.foo is foo_mock

testmodule.py

def foo():
    return 'Bar'

test_async_mock_patch_decorator will fail, because testmodule.foo is <function foo at ###>, not <MagicMock name='foo' id='###'>

Tested this on python3.6 only.

UPDATE:

Seems that on python 3.5.2 there is no such bug. All tests succeeded.

[nicoddemus]

It is kind of tricky to use @mock.patch with pytest because the order of the decorators matter, although I suppose it can be fixed.

Alternatively, you could use pytest-mock for your mocking needs. 😉

[sashgorokhov]

@mock.patch('testmodule.foo')
@pytest.mark.asyncio
async def test_async_mock_patch_decorator(foo_mock):
    assert testmodule.foo is foo_mock

Fails as well.
This bug seems interesting to me. Maybe I could try to fix it?

[Tinche]

By all means, feel free to play around :)

[sashgorokhov]

Seems like the problem here is in mock.patch itself, not pytest-asyncio.
See Martiusweb/asynctest#5 for details. The package asynctest provides a fixed implementation of mock.patch which works just fine and above tests are passing with it.

I am closing this issue since it is not pytest-asyncio issue.

[JackLeo]

is there anything done with mock.patch?

[asvetlov]

Use pytest-mock instead or with mock.patch():.
@mock.patch is ugly, sorry.

[tupui]

As there is no issue with a context manager, an alternative to pytest-mock is to have a fixture which yield the context manager. See here on SO for ref:

@pytest.fixture()
def mocked_worker():
    with patch('test.test_module.os.getcwd', return_value="Testing"):
        result = Worker()
        yield result