diff --git a/almanach/tests/unit/api/auth/test_mixed_auth.py b/almanach/tests/unit/api/auth/test_mixed_auth.py
index 512ede5..1f7ad68 100644
--- a/almanach/tests/unit/api/auth/test_mixed_auth.py
+++ b/almanach/tests/unit/api/auth/test_mixed_auth.py
@@ -12,11 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from flexmock import flexmock
-from hamcrest import assert_that
-from hamcrest import calling
-from hamcrest import equal_to
-from hamcrest import raises
+import mock
 
 from almanach.api.auth import mixed_auth
 from almanach.core import exception
@@ -27,24 +23,34 @@ class TestMixedAuthentication(base.BaseTestCase):
 
     def setUp(self):
         super(TestMixedAuthentication, self).setUp()
-        self.auth_one = flexmock()
-        self.auth_two = flexmock()
+        self.auth_one = mock.Mock()
+        self.auth_two = mock.Mock()
         self.auth_backend = mixed_auth.MixedAuthentication([self.auth_one, self.auth_two])
 
+    def tearDown(self):
+        super(TestMixedAuthentication, self).tearDown()
+
     def test_with_token_valid_with_auth_one(self):
         token = "my token"
-        self.auth_one.should_receive("validate").and_return(True)
-        assert_that(self.auth_backend.validate(token), equal_to(True))
+        self.auth_one.validate.return_value = True
+
+        self.assertEqual(self.auth_backend.validate(token), True)
+        self.auth_one.validate.assert_called_once()
 
     def test_with_token_valid_with_auth_two(self):
         token = "my token"
-        self.auth_one.should_receive("validate").and_raise(exception.AuthenticationFailureException)
-        self.auth_two.should_receive("validate").and_return(True)
-        assert_that(self.auth_backend.validate(token), equal_to(True))
+        self.auth_one.validate.side_effect = exception.AuthenticationFailureException
+        self.auth_two.validate.return_value = True
+
+        self.assertEqual(self.auth_backend.validate(token), True)
+        self.auth_one.validate.assert_called_once()
+        self.auth_two.validate.assert_called_once()
 
     def test_with_token_valid_with_auth_twos(self):
         token = "bad token"
-        self.auth_one.should_receive("validate").and_raise(exception.AuthenticationFailureException)
-        self.auth_two.should_receive("validate").and_raise(exception.AuthenticationFailureException)
-        assert_that(calling(self.auth_backend.validate)
-                    .with_args(token), raises(exception.AuthenticationFailureException))
+        self.auth_one.validate.side_effect = exception.AuthenticationFailureException
+        self.auth_two.validate.side_effect = exception.AuthenticationFailureException
+
+        self.assertRaises(exception.AuthenticationFailureException, self.auth_backend.validate, token)
+        self.auth_one.validate.assert_called_once()
+        self.auth_two.validate.assert_called_once()
diff --git a/almanach/tests/unit/base.py b/almanach/tests/unit/base.py
index 5144225..b777c7a 100644
--- a/almanach/tests/unit/base.py
+++ b/almanach/tests/unit/base.py
@@ -12,7 +12,6 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from flexmock import flexmock_teardown
 from oslo_config import fixture
 import testtools
 
@@ -28,4 +27,3 @@ class BaseTestCase(testtools.TestCase):
 
     def tearDown(self):
         super(BaseTestCase, self).tearDown()
-        flexmock_teardown()