diff --git a/keystoneclient/tests/unit/utils.py b/keystoneclient/tests/unit/utils.py
index 69333763c..22745190a 100644
--- a/keystoneclient/tests/unit/utils.py
+++ b/keystoneclient/tests/unit/utils.py
@@ -16,8 +16,8 @@ import time
 import uuid
 
 import fixtures
-import mock
 from oslo_serialization import jsonutils
+from oslotest import mockpatch
 import requests
 from requests_mock.contrib import fixture
 import six
@@ -43,15 +43,11 @@ class TestCase(testtools.TestCase):
     def setUp(self):
         super(TestCase, self).setUp()
         self.logger = self.useFixture(fixtures.FakeLogger(level=logging.DEBUG))
-        self.time_patcher = mock.patch.object(time, 'time', lambda: 1234)
-        self.time_patcher.start()
+        self.time_patcher = self.useFixture(
+            mockpatch.PatchObject(time, 'time', lambda: 1234)).mock
 
         self.requests_mock = self.useFixture(fixture.Fixture())
 
-    def tearDown(self):
-        self.time_patcher.stop()
-        super(TestCase, self).tearDown()
-
     def stub_url(self, method, parts=None, base_url=None, json=None, **kwargs):
         if not base_url:
             base_url = self.TEST_URL
diff --git a/keystoneclient/tests/unit/v2_0/test_shell.py b/keystoneclient/tests/unit/v2_0/test_shell.py
index 85bbca5f0..6210cfbed 100644
--- a/keystoneclient/tests/unit/v2_0/test_shell.py
+++ b/keystoneclient/tests/unit/v2_0/test_shell.py
@@ -39,7 +39,7 @@ class ShellTests(utils.TestCase):
 
         super(ShellTests, self).setUp()
 
-        self.old_environment = os.environ.copy()
+        self.addCleanup(setattr, os, 'environ', os.environ.copy())
         os.environ = {
             'OS_USERNAME': DEFAULT_USERNAME,
             'OS_PASSWORD': DEFAULT_PASSWORD,
@@ -58,10 +58,6 @@ class ShellTests(utils.TestCase):
 
         self.stub_auth(json=self.token, base_url=DEFAULT_AUTH_URL)
 
-    def tearDown(self):
-        os.environ = self.old_environment
-        super(ShellTests, self).tearDown()
-
     def run_command(self, cmd):
         orig = sys.stdout
         try: