diff --git a/requirements.txt b/requirements.txt
index 2388fd0..3b6428c 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -8,6 +8,7 @@ six>=1.9.0
 testrepository>=0.0.18
 testscenarios>=0.4
 testtools>=1.4.0
-mock>=1.0
+mock>=1.1;python_version!='2.6'
+mock==1.0.1;python_version=='2.6'
 mox3>=0.7.0
 os-client-config>=1.4.0
diff --git a/tests/unit/test_base.py b/tests/unit/test_base.py
index 3cd5d12..8f7567d 100644
--- a/tests/unit/test_base.py
+++ b/tests/unit/test_base.py
@@ -51,7 +51,7 @@ class TestBaseTestCase(testtools.TestCase):
         tc = self.FakeTestCase("test_fake_test")
         tc.setUp()
         env_get_mock.assert_any_call('OS_LOG_CAPTURE')
-        env_get_mock.assert_any_calls('OS_DEBUG')
+        env_get_mock.assert_any_call('OS_DEBUG')
         self.assertFalse(tc.log_fixture.capture_logs)
         self.assertIsNone(tc.log_fixture.logger)
 
@@ -63,7 +63,7 @@ class TestBaseTestCase(testtools.TestCase):
         tc = self.FakeTestCase("test_fake_test")
         tc.setUp()
         env_get_mock.assert_any_call('OS_LOG_CAPTURE')
-        env_get_mock.assert_any_calls('OS_DEBUG')
+        env_get_mock.assert_any_call('OS_DEBUG')
         basic_logger_mock.assert_called_once_with(format=base._LOG_FORMAT,
                                                   level=logging.DEBUG)
 
@@ -76,7 +76,7 @@ class TestBaseTestCase(testtools.TestCase):
         tc = self.FakeTestCase("test_fake_test")
         tc.setUp()
         env_get_mock.assert_any_call('OS_LOG_CAPTURE')
-        env_get_mock.assert_any_calls('OS_DEBUG')
+        env_get_mock.assert_any_call('OS_DEBUG')
         self.assertEqual(fixture_mock.call_count, 5)
 
     def test_mock_patch_cleanup_on_teardown(self):
diff --git a/tests/unit/test_log.py b/tests/unit/test_log.py
index 6a00337..edc7920 100644
--- a/tests/unit/test_log.py
+++ b/tests/unit/test_log.py
@@ -32,7 +32,7 @@ class ConfigureLoggingTestCase(testtools.TestCase):
         f = log.ConfigureLogging()
         f.setUp()
         env_get_mock.assert_any_call('OS_LOG_CAPTURE')
-        env_get_mock.assert_any_calls('OS_DEBUG')
+        env_get_mock.assert_any_call('OS_DEBUG')
         self.assertFalse(f.capture_logs)
         self.assertIsNone(f.logger)
 
@@ -44,7 +44,7 @@ class ConfigureLoggingTestCase(testtools.TestCase):
         f = log.ConfigureLogging()
         f.setUp()
         env_get_mock.assert_any_call('OS_LOG_CAPTURE')
-        env_get_mock.assert_any_calls('OS_DEBUG')
+        env_get_mock.assert_any_call('OS_DEBUG')
         basic_logger_mock.assert_called_once_with(
             format=log.ConfigureLogging.DEFAULT_FORMAT,
             level=logging.DEBUG)
@@ -57,7 +57,7 @@ class ConfigureLoggingTestCase(testtools.TestCase):
         f = log.ConfigureLogging()
         f.setUp()
         env_get_mock.assert_any_call('OS_LOG_CAPTURE')
-        env_get_mock.assert_any_calls('OS_DEBUG')
+        env_get_mock.assert_any_call('OS_DEBUG')
         basic_logger_mock.assert_called_once_with(
             format=log.ConfigureLogging.DEFAULT_FORMAT,
             level=logging.WARNING)
@@ -70,5 +70,5 @@ class ConfigureLoggingTestCase(testtools.TestCase):
         f = log.ConfigureLogging()
         f.setUp()
         env_get_mock.assert_any_call('OS_LOG_CAPTURE')
-        env_get_mock.assert_any_calls('OS_DEBUG')
+        env_get_mock.assert_any_call('OS_DEBUG')
         self.assertIsNotNone(f.logger)