Porting tests to pytest (#33387)

* Porting tests to pytest

* Achievement Get: No longer need mock/generator.py
  * Now done via pytest's parametrization
  * Port safe_eval to pytest
  * Port text tests to pytest
  * Port test_set_mode_if_different to pytest

* Change conftest AnsibleModule fixtures to be more flexible
  * Move the AnsibleModules fixtures to module_utils/conftest.py for sharing
  * Testing the argspec code requires:
    * injecting both the argspec and the arguments.
    * Patching the arguments into sys.stdin at a different level

* More porting to obsolete mock/procenv.py
  * Port run_command to pytest
  * Port known_hosts tests to pytest
  * Port safe_eval to pytest
  * Port test_distribution_version.py to pytest
  * Port test_log to pytest
  * Port test__log_invocation to pytest
  * Remove unneeded import of procenv in test_postgresql

* Port test_pip to pytest style
  * As part of this, create a pytest ansiblemodule fixture in
    modules/conftest.py.  This is slightly different than the
    approach taken in module_utils because here we need to override the
    AnsibleModule that the modules will inherit from instead of one that
    we're instantiating ourselves.

* Fixup usage of parametrization in test_deprecate_warn

* Check that the pip module failed in our test

test/units/module_utils/basic/test_deprecate_warn.py

@@ -1,19 +1,7 @@
 # -*- coding: utf-8 -*-
 #
-# This file is part of Ansible
-#
-# Ansible is free software: you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-#
-# Ansible is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with Ansible.  If not, see <http://www.gnu.org/licenses/>.
+# Copyright (c) 2017 Ansible Project
+# GNU General Public License v3.0+ (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt)
 
 import json
 import sys
@@ -27,49 +15,7 @@ from ansible.module_utils.six import PY3, string_types
 from ansible.module_utils._text import to_bytes
 
 
-@pytest.fixture
-def stdin(mocker, request):
-    if isinstance(request.param, string_types):
-        args = request.param
-    elif isinstance(request.param, MutableMapping):
-        if 'ANSIBLE_MODULE_ARGS' not in request.param:
-            request.param = {'ANSIBLE_MODULE_ARGS': request.param}
-        args = json.dumps(request.param)
-    else:
-        raise Exception('Malformed data to the stdin pytest fixture')
-
-    real_stdin = sys.stdin
-    fake_stdin = BytesIO(to_bytes(args, errors='surrogate_or_strict'))
-    if PY3:
-        sys.stdin = mocker.MagicMock()
-        sys.stdin.buffer = fake_stdin
-    else:
-        sys.stdin = fake_stdin
-
-    yield fake_stdin
-
-    sys.stdin = real_stdin
-
-
-@pytest.fixture
-def am(stdin, request):
-    old_args = ansible.module_utils.basic._ANSIBLE_ARGS
-    ansible.module_utils.basic._ANSIBLE_ARGS = None
-    old_argv = sys.argv
-    sys.argv = ['ansible_unittest']
-
-    am = ansible.module_utils.basic.AnsibleModule(
-        argument_spec=dict(),
-    )
-    am._name = 'ansible_unittest'
-
-    yield am
-
-    ansible.module_utils.basic._ANSIBLE_ARGS = old_args
-    sys.argv = old_argv
-
-
-@pytest.mark.parametrize('stdin', [{}], indirect=True)
+@pytest.mark.parametrize('stdin', [{}], indirect=['stdin'])
 def test_warn(am, capfd):
 
     am.warn('warning1')
@@ -80,7 +26,7 @@ def test_warn(am, capfd):
     assert json.loads(out)['warnings'] == ['warning1', 'warning2']
 
 
-@pytest.mark.parametrize('stdin', [{}], indirect=True)
+@pytest.mark.parametrize('stdin', [{}], indirect=['stdin'])
 def test_deprecate(am, capfd):
     am.deprecate('deprecation1')
     am.deprecate('deprecation2', '2.3')
@@ -99,7 +45,7 @@ def test_deprecate(am, capfd):
     ]
 
 
-@pytest.mark.parametrize('stdin', [{}], indirect=True)
+@pytest.mark.parametrize('stdin', [{}], indirect=['stdin'])
 def test_deprecate_without_list(am, capfd):
     with pytest.raises(SystemExit):
         am.exit_json(deprecations='Simple deprecation warning')