community.general/tests/unit/mock/procenv.py

# (c) 2016, Matt Davis <mdavis@ansible.com>
# (c) 2016, Toshio Kuratomi <tkuratomi@ansible.com>
#
# GNU General Public License v3.0+ (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt)

from __future__ import (absolute_import, division, print_function)
__metaclass__ = type

import sys
import json

from contextlib import contextmanager
from io import BytesIO, StringIO
from ansible_collections.community.general.tests.unit.compat import unittest
from ansible.module_utils.six import PY3
from ansible.module_utils._text import to_bytes


@contextmanager
def swap_stdin_and_argv(stdin_data='', argv_data=tuple()):
    """
    context manager that temporarily masks the test runner's values for stdin and argv
    """
    real_stdin = sys.stdin
    real_argv = sys.argv

    if PY3:
        fake_stream = StringIO(stdin_data)
        fake_stream.buffer = BytesIO(to_bytes(stdin_data))
    else:
        fake_stream = BytesIO(to_bytes(stdin_data))

    try:
        sys.stdin = fake_stream
        sys.argv = argv_data

        yield
    finally:
        sys.stdin = real_stdin
        sys.argv = real_argv


@contextmanager
def swap_stdout():
    """
    context manager that temporarily replaces stdout for tests that need to verify output
    """
    old_stdout = sys.stdout

    if PY3:
        fake_stream = StringIO()
    else:
        fake_stream = BytesIO()

    try:
        sys.stdout = fake_stream

        yield fake_stream
    finally:
        sys.stdout = old_stdout


class ModuleTestCase(unittest.TestCase):
    def setUp(self, module_args=None):
        if module_args is None:
            module_args = {'_ansible_remote_tmp': '/tmp', '_ansible_keep_remote_files': False}

        args = json.dumps(dict(ANSIBLE_MODULE_ARGS=module_args))

        # unittest doesn't have a clean place to use a context manager, so we have to enter/exit manually
        self.stdin_swap = swap_stdin_and_argv(stdin_data=args)
        self.stdin_swap.__enter__()

    def tearDown(self):
        # unittest doesn't have a clean place to use a context manager, so we have to enter/exit manually
        self.stdin_swap.__exit__(None, None, None)