Update utils tests

Signed-off-by: Jan Musial <jan.musial@intel.com>

test/utils_tests/opencas-py-tests/helpers.py

@@ -3,7 +3,7 @@
 # SPDX-License-Identifier: BSD-3-Clause-Clear
 #
 
-import mock
+import unittest.mock as mock
 import re
 import os
 from io import StringIO

test/utils_tests/opencas-py-tests/test_cas_config_01.py

@@ -4,7 +4,7 @@
 #
 
 import pytest
-from mock import patch, mock_open
+from unittest.mock import patch, mock_open
 from textwrap import dedent
 import helpers as h
 

test/utils_tests/opencas-py-tests/test_cas_config_cache_01.py

@@ -4,7 +4,7 @@
 #
 
 import pytest
-import mock
+import unittest.mock as mock
 import stat
 
 import helpers as h

test/utils_tests/opencas-py-tests/test_cas_config_core_01.py

@@ -4,7 +4,7 @@
 #
 
 import pytest
-import mock
+import unittest.mock as mock
 import stat
 
 import helpers as h

test/utils_tests/opencas-py-tests/test_casadm_01.py

@@ -5,7 +5,7 @@
 
 import pytest
 import subprocess
-import mock
+import unittest.mock as mock
 
 from opencas import casadm
 from helpers import get_process_mock

test/utils_tests/opencas-py-tests/test_helper_functions_01.py

@@ -4,7 +4,7 @@
 #
 
 import pytest
-from mock import patch
+from unittest.mock import patch
 import time
 
 import opencas