Use unittest.mock instead of mock

The mock third party library was needed for mock support in py2
runtimes. Since we now only support py36 and later, we can use the
standard lib unittest.mock module instead.

Note that https://github.com/openstack/charms.openstack is used during tests
and he need `mock`, unfortunatelly it doesn't declare `mock` in its
requirements so it retrieve mock from other charm project (cross dependency).
So we depend on charms.openstack first and when
Ib1ed5b598a52375e29e247db9ab4786df5b6d142 will be merged then CI
will pass without errors.

Depends-On: Ib1ed5b598a52375e29e247db9ab4786df5b6d142
Change-Id: Ib658c7f61fe4aceafc1919e366d24ce81ec1dd63

.zuul.yaml

@@ -1,4 +1,4 @@
 - project:
     templates:
-      - openstack-python3-charm-jobs
+      - openstack-python3-ussuri-jobs
       - openstack-cover-jobs

test-requirements.txt

@@ -13,11 +13,7 @@ setuptools<50.0.0  # https://github.com/pypa/setuptools/commit/04e3df22df840c6bb
 
 requests>=2.18.4
 
-# Newer mock seems to have some syntax which is newer than python3.5 (e.g.
-# f'{something}'
-mock>=1.2,<4.0.0; python_version < '3.6'
-mock>=1.2; python_version >= '3.6'
-
+flake8>=2.2.4,<=2.4.1
 stestr>=2.2.0
 
 # Dependency of stestr. Workaround for

unit_tests/test_actions_add_disk.py

@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import mock
+from unittest import mock
 
 from actions import add_disk
 

unit_tests/test_actions_blacklist.py

@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import mock
+from unittest import mock
 
 from charmhelpers.core import hookenv
 

unit_tests/test_actions_osd_out_in.py

@@ -11,11 +11,12 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-import mock
-import subprocess
 
+import subprocess
 import sys
 
+from unittest import mock
+
 from test_utils import CharmTestCase
 
 sys.path.append('hooks')

unit_tests/test_actions_service.py

@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import mock
+import unittest.mock as mock
 from contextlib import contextmanager
 
 from actions import service

unit_tests/test_actions_zap_disk.py

@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import mock
+from unittest import mock
 
 from actions import zap_disk
 

unit_tests/test_ceph_hooks.py

@@ -17,7 +17,7 @@ from collections import OrderedDict
 import copy
 import unittest
 
-from mock import patch, MagicMock, call
+from unittest.mock import patch, MagicMock, call
 
 import charmhelpers.contrib.storage.linux.ceph as ceph
 

unit_tests/test_ceph_utils.py

@@ -15,7 +15,7 @@
 
 import unittest
 
-from mock import patch
+from unittest.mock import patch
 
 with patch('charmhelpers.contrib.hardening.harden.harden') as mock_dec:
     mock_dec.side_effect = (lambda *dargs, **dkwargs: lambda f:

unit_tests/test_config.py

@@ -18,7 +18,7 @@ import tempfile
 import sys
 import test_utils
 
-from mock import patch, MagicMock
+from unittest.mock import patch, MagicMock
 
 # python-apt is not installed as part of test-requirements but is imported by
 # some charmhelpers modules so create a fake import.

unit_tests/test_status.py

@@ -12,10 +12,10 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import mock
+from unittest import mock
 import test_utils
 
-from mock import MagicMock, patch
+from unittest.mock import MagicMock, patch
 
 with patch('charmhelpers.contrib.hardening.harden.harden') as mock_dec:
     mock_dec.side_effect = (lambda *dargs, **dkwargs: lambda f:

unit_tests/test_tuning.py

@@ -1,5 +1,5 @@
 __author__ = 'Chris Holcombe <chris.holcombe@canonical.com>'
-from mock import patch, call
+from unittest.mock import patch, call
 import test_utils
 import charms_ceph.utils as ceph
 

unit_tests/test_upgrade.py

@@ -1,4 +1,4 @@
-from mock import call, patch
+from unittest.mock import call, patch
 from test_utils import CharmTestCase
 from ceph_hooks import check_for_upgrade, notify_mon_of_upgrade
 

unit_tests/test_utils.py

@@ -19,7 +19,7 @@ import sys
 import yaml
 
 from contextlib import contextmanager
-from mock import patch, MagicMock
+from unittest.mock import patch, MagicMock
 
 # python-apt is not installed as part of test-requirements but is imported by
 # some charmhelpers modules so create a fake import.