diff --git a/n2vc/tests/unit/test_libjuju.py b/n2vc/tests/unit/test_libjuju.py
index 454b87f..7bea6b3 100644
--- a/n2vc/tests/unit/test_libjuju.py
+++ b/n2vc/tests/unit/test_libjuju.py
@@ -272,7 +272,8 @@
         super(GetModelTest, self).setUp()
 
     def test_get_model(
-        self, mock_get_model,
+        self,
+        mock_get_model,
     ):
         mock_get_model.return_value = juju.model.Model()
         model = self.loop.run_until_complete(
@@ -288,7 +289,9 @@
         super(ModelExistsTest, self).setUp()
 
     async def test_existing_model(
-        self, mock_list_models, mock_get_controller,
+        self,
+        mock_list_models,
+        mock_get_controller,
     ):
         mock_list_models.return_value = ["existing_model"]
         self.assertTrue(
@@ -299,7 +302,10 @@
 
     @asynctest.mock.patch("n2vc.libjuju.Libjuju.disconnect_controller")
     async def test_no_controller(
-        self, mock_disconnect_controller, mock_list_models, mock_get_controller,
+        self,
+        mock_disconnect_controller,
+        mock_list_models,
+        mock_get_controller,
     ):
         mock_list_models.return_value = ["existing_model"]
         mock_get_controller.return_value = juju.controller.Controller()
@@ -307,7 +313,9 @@
         mock_disconnect_controller.assert_called_once()
 
     async def test_non_existing_model(
-        self, mock_list_models, mock_get_controller,
+        self,
+        mock_list_models,
+        mock_get_controller,
     ):
         mock_list_models.return_value = ["existing_model"]
         self.assertFalse(
@@ -551,7 +559,12 @@
         application = None
         with self.assertRaises(JujuApplicationExists):
             application = self.loop.run_until_complete(
-                self.libjuju.deploy_charm("existing_app", "path", "model", "machine",)
+                self.libjuju.deploy_charm(
+                    "existing_app",
+                    "path",
+                    "model",
+                    "machine",
+                )
             )
         self.assertIsNone(application)
 
@@ -575,7 +588,12 @@
         application = None
         with self.assertRaises(JujuMachineNotFound):
             application = self.loop.run_until_complete(
-                self.libjuju.deploy_charm("app", "path", "model", "machine",)
+                self.libjuju.deploy_charm(
+                    "app",
+                    "path",
+                    "model",
+                    "machine",
+                )
             )
 
         self.assertIsNone(application)
@@ -601,7 +619,11 @@
         mock_deploy.return_value = FakeApplication()
         application = self.loop.run_until_complete(
             self.libjuju.deploy_charm(
-                "app", "path", "model", "existing_machine", num_units=2,
+                "app",
+                "path",
+                "model",
+                "existing_machine",
+                num_units=2,
             )
         )
 
@@ -651,7 +673,8 @@
         super(GetApplicationTest, self).setUp()
 
     def test_existing_application(
-        self, mock_applications,
+        self,
+        mock_applications,
     ):
         mock_applications.return_value = {"existing_app": "exists"}
         model = juju.model.Model()
@@ -659,7 +682,8 @@
         self.assertEqual(result, "exists")
 
     def test_non_existing_application(
-        self, mock_applications,
+        self,
+        mock_applications,
     ):
         mock_applications.return_value = {"existing_app": "exists"}
         model = juju.model.Model()
@@ -696,7 +720,11 @@
         status = None
         with self.assertRaises(JujuApplicationNotFound):
             output, status = self.loop.run_until_complete(
-                self.libjuju.execute_action("app", "model", "action",)
+                self.libjuju.execute_action(
+                    "app",
+                    "model",
+                    "action",
+                )
             )
         self.assertIsNone(output)
         self.assertIsNone(status)
@@ -722,7 +750,11 @@
         status = None
         with self.assertRaises(JujuActionNotFound):
             output, status = self.loop.run_until_complete(
-                self.libjuju.execute_action("app", "model", "action",)
+                self.libjuju.execute_action(
+                    "app",
+                    "model",
+                    "action",
+                )
             )
         self.assertIsNone(output)
         self.assertIsNone(status)
@@ -752,7 +784,11 @@
         status = None
         with self.assertRaises(JujuLeaderUnitNotFound):
             output, status = self.loop.run_until_complete(
-                self.libjuju.execute_action("app", "model", "action",)
+                self.libjuju.execute_action(
+                    "app",
+                    "model",
+                    "action",
+                )
             )
         self.assertIsNone(output)
         self.assertIsNone(status)
@@ -925,7 +961,11 @@
         mock_add_relation.side_effect = JujuAPIError(result)
 
         self.loop.run_until_complete(
-            self.libjuju.add_relation("model", "app1:relation1", "app2:relation2",)
+            self.libjuju.add_relation(
+                "model",
+                "app1:relation1",
+                "app2:relation2",
+            )
         )
 
         mock_warning.assert_called_with("Relation not found: not found")
@@ -949,7 +989,11 @@
         mock_add_relation.side_effect = JujuAPIError(result)
 
         self.loop.run_until_complete(
-            self.libjuju.add_relation("model", "app1:relation1", "app2:relation2",)
+            self.libjuju.add_relation(
+                "model",
+                "app1:relation1",
+                "app2:relation2",
+            )
         )
 
         mock_warning.assert_called_with("Relation already exists: already exists")
@@ -970,7 +1014,11 @@
 
         with self.assertRaises(JujuAPIError):
             self.loop.run_until_complete(
-                self.libjuju.add_relation("model", "app1:relation1", "app2:relation2",)
+                self.libjuju.add_relation(
+                    "model",
+                    "app1:relation1",
+                    "app2:relation2",
+                )
             )
 
         mock_disconnect_controller.assert_called_once()
@@ -987,7 +1035,11 @@
         mock_get_model.return_value = juju.model.Model()
 
         self.loop.run_until_complete(
-            self.libjuju.add_relation("model", "app1:relation1", "app2:relation2",)
+            self.libjuju.add_relation(
+                "model",
+                "app1:relation1",
+                "app2:relation2",
+            )
         )
 
         mock_add_relation.assert_called_with("app1:relation1", "app2:relation2")
@@ -1005,7 +1057,11 @@
         mock_get_model.return_value = juju.model.Model()
 
         self.loop.run_until_complete(
-            self.libjuju.add_relation("model", "app1:relation1", "saas_name",)
+            self.libjuju.add_relation(
+                "model",
+                "app1:relation1",
+                "saas_name",
+            )
         )
 
         mock_add_relation.assert_called_with("app1:relation1", "saas_name")
@@ -1070,7 +1126,11 @@
         mock_get_application.return_value = FakeApplication()
 
         self.loop.run_until_complete(
-            self.libjuju.configure_application("model", "app", {"config"},)
+            self.libjuju.configure_application(
+                "model",
+                "app",
+                {"config"},
+            )
         )
         mock_get_application.assert_called_once()
         mock_disconnect_controller.assert_called_once()
@@ -1089,11 +1149,64 @@
 
         with self.assertRaises(Exception):
             self.loop.run_until_complete(
-                self.libjuju.configure_application("model", "app", {"config"},)
+                self.libjuju.configure_application(
+                    "model",
+                    "app",
+                    {"config"},
+                )
             )
         mock_disconnect_controller.assert_called_once()
         mock_disconnect_model.assert_called_once()
 
+    def test_controller_exception(
+        self,
+        mock_get_application,
+        mock_disconnect_controller,
+        mock_disconnect_model,
+        mock_get_model,
+        mock_get_controller,
+    ):
+
+        result = {"error": "not found", "response": "response", "request-id": 1}
+
+        mock_get_controller.side_effect = JujuAPIError(result)
+
+        with self.assertRaises(JujuAPIError):
+            self.loop.run_until_complete(
+                self.libjuju.configure_application(
+                    "model",
+                    "app",
+                    {"config"},
+                )
+            )
+        mock_get_model.assert_not_called()
+        mock_disconnect_controller.assert_not_called()
+        mock_disconnect_model.assert_not_called()
+
+    def test_get_model_exception(
+        self,
+        mock_get_application,
+        mock_disconnect_controller,
+        mock_disconnect_model,
+        mock_get_model,
+        mock_get_controller,
+    ):
+
+        result = {"error": "not found", "response": "response", "request-id": 1}
+        mock_get_model.side_effect = JujuAPIError(result)
+
+        with self.assertRaises(JujuAPIError):
+            self.loop.run_until_complete(
+                self.libjuju.configure_application(
+                    "model",
+                    "app",
+                    {"config"},
+                )
+            )
+        mock_get_model.assert_called_once()
+        mock_disconnect_controller.assert_called_once()
+        mock_disconnect_model.assert_not_called()
+
 
 # TODO _get_api_endpoints_db test case
 # TODO _update_api_endpoints_db test case
@@ -1108,7 +1221,10 @@
         super(ListModelsTest, self).setUp()
 
     def test_containing(
-        self, mock_list_models, mock_disconnect_controller, mock_get_controller,
+        self,
+        mock_list_models,
+        mock_disconnect_controller,
+        mock_get_controller,
     ):
         mock_get_controller.return_value = juju.controller.Controller()
         mock_list_models.return_value = ["existingmodel"]
@@ -1118,7 +1234,10 @@
         self.assertEquals(models, ["existingmodel"])
 
     def test_not_containing(
-        self, mock_list_models, mock_disconnect_controller, mock_get_controller,
+        self,
+        mock_list_models,
+        mock_disconnect_controller,
+        mock_get_controller,
     ):
         mock_get_controller.return_value = juju.controller.Controller()
         mock_list_models.return_value = ["existingmodel", "model"]
@@ -1128,7 +1247,10 @@
         self.assertEquals(models, [])
 
     def test_no_contains_arg(
-        self, mock_list_models, mock_disconnect_controller, mock_get_controller,
+        self,
+        mock_list_models,
+        mock_disconnect_controller,
+        mock_get_controller,
     ):
         mock_get_controller.return_value = juju.controller.Controller()
         mock_list_models.return_value = ["existingmodel", "model"]
@@ -1180,7 +1302,10 @@
         super(ListOffers, self).setUp()
 
     def test_disconnect_controller(
-        self, mock_list_offers, mock_disconnect_controller, mock_get_controller,
+        self,
+        mock_list_offers,
+        mock_disconnect_controller,
+        mock_get_controller,
     ):
         mock_get_controller.return_value = juju.controller.Controller()
         mock_list_offers.side_effect = Exception()
@@ -1189,7 +1314,10 @@
         mock_disconnect_controller.assert_called_once()
 
     def test_empty_list(
-        self, mock_list_offers, mock_disconnect_controller, mock_get_controller,
+        self,
+        mock_list_offers,
+        mock_disconnect_controller,
+        mock_get_controller,
     ):
         mock_get_controller.return_value = juju.controller.Controller()
         mock_list_offers.return_value = []
@@ -1198,7 +1326,10 @@
         mock_disconnect_controller.assert_called_once()
 
     def test_non_empty_list(
-        self, mock_list_offers, mock_disconnect_controller, mock_get_controller,
+        self,
+        mock_list_offers,
+        mock_disconnect_controller,
+        mock_get_controller,
     ):
         mock_get_controller.return_value = juju.controller.Controller()
         mock_list_offers.return_value = ["offer"]
@@ -1435,7 +1566,10 @@
         super(RemoveCloudTest, self).setUp()
 
     def test_remove_cloud(
-        self, mock_remove_cloud, mock_disconnect_controller, mock_get_controller,
+        self,
+        mock_remove_cloud,
+        mock_disconnect_controller,
+        mock_get_controller,
     ):
         mock_get_controller.return_value = juju.controller.Controller()
 
@@ -1444,7 +1578,10 @@
         mock_disconnect_controller.assert_called_once()
 
     def test_remove_cloud_exception(
-        self, mock_remove_cloud, mock_disconnect_controller, mock_get_controller,
+        self,
+        mock_remove_cloud,
+        mock_disconnect_controller,
+        mock_get_controller,
     ):
         mock_get_controller.return_value = juju.controller.Controller()
         mock_remove_cloud.side_effect = Exception()
@@ -1473,7 +1610,8 @@
         except JujuInvalidK8sConfiguration as e:
             exception_raised = True
             self.assertEqual(
-                e.message, "authentication method not supported",
+                e.message,
+                "authentication method not supported",
             )
         self.assertTrue(exception_raised)
 
@@ -1564,7 +1702,8 @@
         self.assertEqual(
             credential,
             juju.client._definitions.CloudCredential(
-                attrs={"ClientKeyData": "key", "Token": "Token"}, auth_type="oauth2",
+                attrs={"ClientKeyData": "key", "Token": "Token"},
+                auth_type="oauth2",
             ),
         )
 
@@ -1584,7 +1723,8 @@
         except JujuInvalidK8sConfiguration as e:
             exception_raised = True
             self.assertEqual(
-                e.message, "missing token for auth type oauth2",
+                e.message,
+                "missing token for auth type oauth2",
             )
         self.assertTrue(exception_raised)
 
@@ -1601,7 +1741,8 @@
         except JujuInvalidK8sConfiguration as e:
             exception_raised = True
             self.assertEqual(
-                e.message, "unknown format of api_key",
+                e.message,
+                "unknown format of api_key",
             )
         self.assertTrue(exception_raised)
 
@@ -1618,6 +1759,7 @@
         except JujuInvalidK8sConfiguration as e:
             exception_raised = True
             self.assertEqual(
-                e.message, "Cannot set both token and user/pass",
+                e.message,
+                "Cannot set both token and user/pass",
             )
         self.assertTrue(exception_raised)