Combining mock patch with pytest's tmpdir fixture

foo.py

import argparse


def bar():
    parser = argparse.ArgumentParser()
    parser.add_argument('a')
    parser.add_argument('b')
    parser.add_argument('c')
    args = parser.parse_args()
    return args


def foobar():
    args = bar()
    print(args)
    return args


if __name__ == '__main__':
    foobar()

goo.py

import argparse

from gooey import Gooey


@Gooey
def bar():
    parser = argparse.ArgumentParser()
    parser.add_argument('a')
    parser.add_argument('b')
    parser.add_argument('c')
    args = parser.parse_args()
    return args


def foobar():
    args = bar()
    print(args)
    return args


if __name__ == '__main__':
    foobar()

test_foo.py

import argparse
import os
import sys
from unittest.mock import patch

import pytest

import foo


def test_foobar(tmpdir):
    args = argparse.Namespace()
    args.a = 1
    args.b = tmpdir
    args.c = 3
    with patch('foo.bar') as mock_bar:
        mock_bar.return_value = args
        result = foo.foobar()
        assert result.a == args.a
        assert args.b == tmpdir
    mock_bar.assert_called


def test_main(tmpdir):
    sys.argv = ['foo.py', '1', tmpdir, '3']
    with patch('foo.bar') as mock_bar:
        args = argparse.Namespace()
        args.a = 1
        args.b = tmpdir
        args.c = 3
        mock_bar.return_value = args
        os.system('foo.py 1 ' + str(tmpdir) + ' 3')
    mock_bar.assert_called

test_goo.py

import argparse
import os
import sys
from unittest.mock import patch

import pytest

import goo


def test_foobar(tmpdir):
    args = argparse.Namespace()
    args.a = 1
    args.b = tmpdir
    args.c = 3
    with patch('goo.bar') as mock_bar:
        mock_bar.return_value = args
        result = goo.foobar()
        assert result.a == args.a
        assert args.b == tmpdir
    mock_bar.assert_called


def test_main(tmpdir):
    sys.argv = ['goo.py', '1', tmpdir, '3']
    with patch('goo.bar') as mock_bar:
        args = argparse.Namespace()
        args.a = 1
        args.b = tmpdir
        args.c = 3
        mock_bar.return_value = args
        os.system('goo.py --ignore-gooey 1 ' + str(tmpdir) + ' 3')
    mock_bar.assert_called