run executables in subprocesses in temporary directory

test_ls.py

# requires ls/a.file in the root directory
import os
import subprocess
import shutil
import tempfile
import pytest

def mk_cd_tempdir(path, suffix=''):
    cur_dir = os.path.abspath(os.path.curdir)
    test_dir = tempfile.mkdtemp(suffix=suffix)
    shutil.copytree(path, os.path.join(test_dir, path))
    os.chdir(test_dir)
    yield test_dir
    os.chdir(cur_dir)
    #shutil.rmtree(test_dir)

@pytest.fixture()
def ls_dirs():
    # with python >= 3.5
    # yield from mk_cd_tempdir
    for td in mk_cd_tempdir('ls', '_ls_test'):
        yield td

def test_ls(ls_dirs):
    test_dir = ls_dirs
    output = subprocess.check_output(['ls', 'ls'])
    assert b'a.file' in output