Remove mock as test requirement

Now that we have moved to py36 and later runtimes, we no longer need
to use the third party mock library and can only use the standard
library unittest.mock instead.

Change-Id: I8994aaadaf2feb806e70e1ea6dc87157012d1334
Signed-off-by: Gael Chamoulaud (Strider) <gchamoul@redhat.com>

lower-constraints.txt

@@ -114,4 +114,3 @@ urllib3==1.22
 warlock==1.3.0
 websocket-client==0.47.0
 wrapt==1.10.11
-mock==2.0.0

test-requirements.txt

@@ -15,4 +15,3 @@ testtools>=2.2.0 # MIT
 reno>=3.1.0 # Apache-2.0
 netaddr>=0.7.18 # BSD
 pre-commit # MIT
-mock>=2.0.0 # BSD

tripleo_validations/tests/library/test_check_ironic_boot_config.py

@@ -13,7 +13,10 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
-from unittest import mock
+try:
+    from unittest import mock
+except ImportError:
+    import mock
 
 import library.check_ironic_boot_config as validation
 from tripleo_validations.tests import base

tripleo_validations/tests/library/test_check_package_update.py

@@ -12,8 +12,12 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
-from mock import MagicMock
-from mock import patch
+try:
+    from unittest.mock import MagicMock
+    from unittest.mock import patch
+except ImportError:
+    from mock import MagicMock
+    from mock import patch
 
 from library.check_package_update import check_update
 from library.check_package_update import get_package_details

tripleo_validations/tests/library/test_ovs_dpdk_pmd_cpus_check.py

@@ -13,9 +13,12 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
-
-from mock import MagicMock
-from mock import patch
+try:
+    from unittest.mock import MagicMock
+    from unittest.mock import patch
+except ImportError:
+    from mock import MagicMock
+    from mock import patch
 
 import library.ovs_dpdk_pmd_cpus_check as validation
 from tripleo_validations.tests import base