Use unittest.mock instead of PyPI mock

Now that py2 is gone, oslotest dropped dependency on mock and will
soon affect Ussuri CI [1], let's use unittest.mock built in py3.

This also fixes py38 jobs and proactively prevents py36 and py37
failing due to [1]. This is because we never included mock in
test-requirements (but in lower-constraints where it does not
really belong at all) and instead relied on oslotest to bring
it in.

[1] https://review.opendev.org/716322

Change-Id: Iceedcc7ad0d087414f6f94dfc0235fda4754be63

2 files changed, 2 insertions, 2 deletions

diff --git a/tests/test_build.py b/tests/test_build.py
index 632931ee4..c4a4a6aed 100644
--- a/tests/test_build.py
+++ b/tests/test_build.py
@@ -13,8 +13,8 @@
 import multiprocessing
 import os
 import sys
+from unittest.mock import patch
 
-from mock import patch
 from oslo_log import fixture as log_fixture
 from oslo_log import log as logging
 from oslotest import base
diff --git a/tests/test_set_config.py b/tests/test_set_config.py
index e4706c99d..7016d8fa3 100644
--- a/tests/test_set_config.py
+++ b/tests/test_set_config.py
@@ -13,9 +13,9 @@
 import copy
 import imp
 import json
-import mock
 import os.path
 import sys
+from unittest import mock
 
 from oslotest import base