Feature 10509 manual scaling for native k8s charm

Juju version has to be upgraded to 2.8.6 because of a typo error.
You can see bug report: https://github.com/juju/python-libjuju/issues/477
and release note: https://github.com/juju/python-libjuju/commit/facd1f19eae65728b6c7c3b823939bb35ae45ed2

Change-Id: Iae4262e64debdf6b4d36b37778ec29f0dd46bac1
Signed-off-by: aktas <emin.aktas@ulakhaberlesme.com.tr>
diff --git a/n2vc/tests/unit/test_libjuju.py b/n2vc/tests/unit/test_libjuju.py
index fde6817..5b120b1 100644
--- a/n2vc/tests/unit/test_libjuju.py
+++ b/n2vc/tests/unit/test_libjuju.py
@@ -1887,3 +1887,106 @@
                 "Cannot set both token and user/pass",
             )
         self.assertTrue(exception_raised)
+
+
+@asynctest.mock.patch("n2vc.libjuju.Libjuju.get_controller")
+@asynctest.mock.patch("n2vc.libjuju.Libjuju.get_model")
+@asynctest.mock.patch("n2vc.libjuju.Libjuju._get_application")
+@asynctest.mock.patch("n2vc.libjuju.Libjuju.disconnect_model")
+@asynctest.mock.patch("n2vc.libjuju.Libjuju.disconnect_controller")
+@asynctest.mock.patch("n2vc.juju_watcher.JujuModelWatcher.wait_for_model")
+class ScaleApplicationTest(LibjujuTestCase):
+    def setUp(self):
+        super(ScaleApplicationTest, self).setUp()
+
+    @asynctest.mock.patch("asyncio.sleep")
+    def test_scale_application(
+        self,
+        mock_sleep,
+        mock_wait_for_model,
+        mock_disconnect_controller,
+        mock_disconnect_model,
+        mock_get_application,
+        mock_get_model,
+        mock_get_controller,
+    ):
+        mock_get_model.return_value = juju.model.Model()
+        mock_get_application.return_value = FakeApplication()
+        self.loop.run_until_complete(
+            self.libjuju.scale_application(
+                "model",
+                "app",
+                2
+            )
+        )
+        mock_wait_for_model.assert_called_once()
+        mock_disconnect_controller.assert_called_once()
+        mock_disconnect_model.assert_called_once()
+
+    def test_no_application(
+        self,
+        mock_wait_for,
+        mock_disconnect_controller,
+        mock_disconnect_model,
+        mock_get_application,
+        mock_get_model,
+        mock_get_controller,
+    ):
+        mock_get_application.return_value = None
+        mock_get_model.return_value = juju.model.Model()
+        with self.assertRaises(JujuApplicationNotFound):
+            self.loop.run_until_complete(
+                self.libjuju.scale_application(
+                    "model",
+                    "app",
+                    2
+                )
+            )
+        mock_disconnect_controller.assert_called()
+        mock_disconnect_model.assert_called()
+
+    def test_exception(
+            self,
+            mock_wait_for,
+            mock_disconnect_controller,
+            mock_disconnect_model,
+            mock_get_application,
+            mock_get_model,
+            mock_get_controller,
+    ):
+        mock_get_model.return_value = None
+        mock_get_application.return_value = FakeApplication()
+        with self.assertRaises(Exception):
+            self.loop.run_until_complete(
+                self.libjuju.scale_application(
+                    "model",
+                    "app",
+                    2,
+                    total_timeout=0
+                )
+            )
+        mock_disconnect_controller.assert_called_once()
+
+
+@asynctest.mock.patch("n2vc.libjuju.Libjuju._get_application")
+class GetUnitNumberTest(LibjujuTestCase):
+    def setUp(self):
+        super(GetUnitNumberTest, self).setUp()
+
+    def test_succesful_get_unit_number(
+        self,
+        mock_get_applications,
+    ):
+        mock_get_applications.return_value = FakeApplication()
+        model = juju.model.Model()
+        result = self.libjuju._get_application_count(model, "app")
+        self.assertEqual(result, 2)
+
+    def test_non_existing_application(
+        self,
+        mock_get_applications,
+    ):
+        mock_get_applications.return_value = None
+        model = juju.model.Model()
+        result = self.libjuju._get_application_count(model, "app")
+        self.assertEqual(result, None)