Use unittest.mock instead of third party mock

Now that we no longer support py27, we can use the standard library
unittest.mock module instead of the third party mock lib.

The remainder was auto-generated with the following (hacky) script, with
one or two manual tweaks after the fact:

  import glob

  for path in glob.glob('watcher/tests/**/*.py', recursive=True):
      with open(path) as fh:
          lines = fh.readlines()
      if 'import mock\n' not in lines:
          continue
      import_group_found = False
      create_first_party_group = False
      for num, line in enumerate(lines):
          line = line.strip()
          if line.startswith('import ') or line.startswith('from '):
              tokens = line.split()
              for lib in (
                  'ddt', 'six', 'webob', 'fixtures', 'testtools'
                  'neutron', 'cinder', 'ironic', 'keystone', 'oslo',
              ):
                  if lib in tokens[1]:
                      create_first_party_group = True
                      break
              if create_first_party_group:
                  break
              import_group_found = True
          if not import_group_found:
              continue
          if line.startswith('import ') or line.startswith('from '):
              tokens = line.split()
              if tokens[1] > 'unittest':
                  break
              elif tokens[1] == 'unittest' and (
                  len(tokens) == 2 or tokens[4] > 'mock'
              ):
                  break
          elif not line:
              break
      if create_first_party_group:
          lines.insert(num, 'from unittest import mock\n\n')
      else:
          lines.insert(num, 'from unittest import mock\n')
      del lines[lines.index('import mock\n')]
      with open(path, 'w+') as fh:
          fh.writelines(lines)

Co-Authored-By: Sean McGinnis <sean.mcginnis@gmail.com>

Change-Id: Icf35d3a6c10c529e07d1a4edaa36f504e5bf553a

watcher/tests/common/loader/test_loader.py

@@ -14,7 +14,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import mock
+from unittest import mock
 
 from oslo_config import cfg
 from stevedore import driver as drivermanager

watcher/tests/common/test_cinder_helper.py

@@ -13,8 +13,8 @@
 # limitations under the License.
 #
 
-import mock
 import time
+from unittest import mock
 
 from cinderclient import exceptions as cinder_exception
 

watcher/tests/common/test_clients.py

@@ -12,6 +12,8 @@
 
 from ceilometerclient import client as ceclient
 import ceilometerclient.v2.client as ceclient_v2
+from unittest import mock
+
 from cinderclient import client as ciclient
 from cinderclient.v3 import client as ciclient_v3
 from glanceclient import client as glclient
@@ -21,7 +23,6 @@ from ironicclient import client as irclient
 from ironicclient.v1 import client as irclient_v1
 from keystoneauth1 import adapter as ka_adapter
 from keystoneauth1 import loading as ka_loading
-import mock
 from monascaclient import client as monclient
 from monascaclient.v2_0 import client as monclient_v2
 from neutronclient.neutron import client as netclient

watcher/tests/common/test_ironic_helper.py

@@ -17,7 +17,7 @@
 # limitations under the License.
 #
 
-import mock
+from unittest import mock
 
 from watcher.common import clients
 from watcher.common import exception

watcher/tests/common/test_nova_helper.py

@@ -18,10 +18,10 @@
 #
 
 import time
+from unittest import mock
 
 from novaclient import api_versions
 
-import mock
 
 import glanceclient.exc as glexceptions
 import novaclient.exceptions as nvexceptions

watcher/tests/common/test_placement_helper.py

@@ -11,7 +11,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import mock
+from unittest import mock
 
 from watcher.common import placement_helper
 from watcher.tests import base

watcher/tests/common/test_service.py

@@ -15,7 +15,7 @@
 # limitations under the License.
 
 
-import mock
+from unittest import mock
 
 from oslo_config import cfg