diff --git a/nova/tests/unit/virt/libvirt/test_designer.py b/nova/tests/unit/virt/libvirt/test_designer.py
index 649144c0d1..c6d23e5fba 100644
--- a/nova/tests/unit/virt/libvirt/test_designer.py
+++ b/nova/tests/unit/virt/libvirt/test_designer.py
@@ -12,11 +12,17 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
+import mock
+
+from nova.pci import utils as pci_utils
 from nova import test
+from nova.tests.unit import matchers
+from nova.virt.libvirt import config
 from nova.virt.libvirt import designer
 
 
 class DesignerTestCase(test.NoDBTestCase):
+
     def test_set_vif_bandwidth_config_no_extra_specs(self):
         # Test whether test_set_vif_bandwidth_config_no_extra_specs fails when
         # its second parameter has no 'extra_specs' field.
@@ -28,3 +34,145 @@ class DesignerTestCase(test.NoDBTestCase):
             designer.set_vif_bandwidth_config(None, {})
         except KeyError as e:
             self.fail('KeyError: %s' % e)
+
+    def test_set_vif_guest_frontend_config(self):
+        conf = config.LibvirtConfigGuestInterface()
+        designer.set_vif_guest_frontend_config(conf, 'fake-mac',
+                                               'fake-model', 'fake-driver',
+                                               'fake-queues')
+        self.assertEqual('fake-mac', conf.mac_addr)
+        self.assertEqual('fake-model', conf.model)
+        self.assertEqual('fake-driver', conf.driver_name)
+        self.assertEqual('fake-queues', conf.vhost_queues)
+
+    def test_set_vif_host_backend_bridge_config(self):
+        conf = config.LibvirtConfigGuestInterface()
+        designer.set_vif_host_backend_bridge_config(conf, 'fake-bridge',
+                                                    'fake-tap')
+        self.assertEqual('bridge', conf.net_type)
+        self.assertEqual('fake-bridge', conf.source_dev)
+        self.assertEqual('fake-tap', conf.target_dev)
+
+    def test_set_vif_host_backend_ethernet_config(self):
+        conf = config.LibvirtConfigGuestInterface()
+        designer.set_vif_host_backend_ethernet_config(conf, 'fake-tap')
+        self.assertEqual('ethernet', conf.net_type)
+        self.assertEqual('fake-tap', conf.target_dev)
+        self.assertEqual('', conf.script)
+
+    def test_set_vif_host_backend_ovs_config(self):
+        conf = config.LibvirtConfigGuestInterface()
+        designer.set_vif_host_backend_ovs_config(conf, 'fake-bridge',
+                                                 'fake-interface', 'fake-tap')
+        self.assertEqual('bridge', conf.net_type)
+        self.assertEqual('fake-bridge', conf.source_dev)
+        self.assertEqual('openvswitch', conf.vporttype)
+        self.assertEqual('fake-tap', conf.target_dev)
+
+    def test_set_vif_host_backend_802qbg_config(self):
+        conf = config.LibvirtConfigGuestInterface()
+        designer.set_vif_host_backend_802qbg_config(conf, 'fake-devname',
+                                                    'fake-managerid',
+                                                    'fake-typeid',
+                                                    'fake-typeidversion',
+                                                    'fake-instanceid',
+                                                    'fake-tap')
+        self.assertEqual('direct', conf.net_type)
+        self.assertEqual('fake-devname', conf.source_dev)
+        self.assertEqual('vepa', conf.source_mode)
+        self.assertEqual('802.1Qbg', conf.vporttype)
+        expected = [{'key': 'managerid', 'value': 'fake-managerid'},
+                    {'key': 'typeid', 'value': 'fake-typeid'},
+                    {'key': 'typeidversion', 'value': 'fake-typeidversion'},
+                    {'key': 'instanceid', 'value': 'fake-instanceid'}]
+        self.assertThat(expected, matchers.DictListMatches(conf.vportparams))
+        self.assertEqual('fake-tap', conf.target_dev)
+
+    @mock.patch.object(pci_utils, 'get_ifname_by_pci_address',
+                       return_value='fake-devname')
+    def test_set_vif_host_backend_802qbh_config_direct(self,
+                                                       mock_pci):
+        conf = config.LibvirtConfigGuestInterface()
+        designer.set_vif_host_backend_802qbh_config(conf, 'direct',
+                                                    'fake-pci-dev',
+                                                    'fake-profileid',
+                                                    'fake-tap')
+        self.assertEqual('direct', conf.net_type)
+        self.assertEqual('fake-devname', conf.source_dev)
+        self.assertEqual('passthrough', conf.source_mode)
+        self.assertEqual('vhost', conf.driver_name)
+        mock_pci.assert_called_with('fake-pci-dev')
+        self.assertEqual('802.1Qbh', conf.vporttype)
+        self.assertEqual('fake-tap', conf.target_dev)
+
+    def test_set_vif_host_backend_802qbh_config_hostdev(self):
+        conf = config.LibvirtConfigGuestInterface()
+        designer.set_vif_host_backend_802qbh_config(conf, 'hostdev',
+                                                    'fake-devname',
+                                                    'fake-profileid',
+                                                    'fake-tap')
+        self.assertEqual('hostdev', conf.net_type)
+        self.assertEqual('fake-devname', conf.source_dev)
+        self.assertIsNone(conf.model)
+        self.assertEqual('802.1Qbh', conf.vporttype)
+        self.assertEqual('fake-tap', conf.target_dev)
+
+    @mock.patch.object(pci_utils, 'get_ifname_by_pci_address',
+                       return_value='fake-devname')
+    def test_set_vif_host_backend_hw_veb_direct(self,
+                                                mock_pci):
+        conf = config.LibvirtConfigGuestInterface()
+        designer.set_vif_host_backend_hw_veb(conf, 'direct',
+                                             'fake-pci-dev',
+                                             'fake-vlan',
+                                             'fake-tap')
+        self.assertEqual('direct', conf.net_type)
+        self.assertEqual('fake-devname', conf.source_dev)
+        self.assertEqual('passthrough', conf.source_mode)
+        self.assertEqual('vhost', conf.driver_name)
+        self.assertEqual('fake-tap', conf.target_dev)
+        mock_pci.assert_called_with('fake-pci-dev')
+
+    def test_set_vif_host_backend_hw_veb_hostdev(self):
+        conf = config.LibvirtConfigGuestInterface()
+        designer.set_vif_host_backend_hw_veb(conf, 'hostdev',
+                                             'fake-devname',
+                                             'fake-vlan',
+                                             'fake-tap')
+        self.assertEqual('hostdev', conf.net_type)
+        self.assertEqual('fake-devname', conf.source_dev)
+        self.assertIsNone(conf.model)
+        self.assertEqual('fake-vlan', conf.vlan)
+        self.assertEqual('fake-tap', conf.target_dev)
+
+    @mock.patch.object(pci_utils, 'get_pci_address_fields',
+                       return_value=('fake-domain', 'fake-bus',
+                                     'fake-slot', 'fake-function'))
+    def test_set_vif_host_backend_ib_hostdev_config(self,
+                                                    mock_pci_fields):
+        conf = config.LibvirtConfigGuestInterface()
+        designer.set_vif_host_backend_ib_hostdev_config(conf,
+                                                        'fake-pci-slot')
+        self.assertEqual('fake-domain', conf.domain)
+        self.assertEqual('fake-bus', conf.bus)
+        self.assertEqual('fake-slot', conf.slot)
+        self.assertEqual('fake-function', conf.function)
+        mock_pci_fields.assert_called_with('fake-pci-slot')
+
+    def test_set_vif_host_backend_direct_config(self):
+        conf = config.LibvirtConfigGuestInterface()
+        designer.set_vif_host_backend_direct_config(conf, 'fake-devname',
+                                                    mode="passthrough")
+        self.assertEqual('direct', conf.net_type)
+        self.assertEqual('fake-devname', conf.source_dev)
+        self.assertEqual('passthrough', conf.source_mode)
+        self.assertEqual('virtio', conf.model)
+
+    def test_set_vif_host_backend_vhostuser_config(self):
+        conf = config.LibvirtConfigGuestInterface()
+        designer.set_vif_host_backend_vhostuser_config(conf, 'fake-mode',
+                                                       'fake-path')
+        self.assertEqual('vhostuser', conf.net_type)
+        self.assertEqual('unix', conf.vhostuser_type)
+        self.assertEqual('fake-mode', conf.vhostuser_mode)
+        self.assertEqual('fake-path', conf.vhostuser_path)