[tests] Add tests for config status update on org/group variable change

Fixes openwisp#1070

Add tests to verify that when organization or device group
configuration variables change, the config status updates to
"modified" only for devices whose rendered configuration is
actually affected by the change.

Author: mn-ram

openwisp_controller/config/tests/test_device.py

@@ -433,6 +433,61 @@ def test_changing_group_variable_invalidates_cache(self):
         new_checksum = config.get_cached_checksum()
         self.assertNotEqual(old_checksum, new_checksum)
 
+    def test_status_update_on_org_variable_change(self):
+        org = self._get_org()
+        cs = OrganizationConfigSettings.objects.create(organization=org, context={})
+        c1 = self._create_config(organization=org)
+        c1.templates.add(
+            self._create_template(
+                name="t-with-var",
+                config={"interfaces": [{"name": "eth0", "type": "{{ ssid }}"}]},
+                default_values={"ssid": "default"},
+            )
+        )
+        c1.set_status_applied()
+        d2 = self._create_device(
+            organization=org, name="d2", mac_address="00:11:22:33:44:56"
+        )
+        c2 = self._create_config(device=d2)
+        c2.set_status_applied()
+        cs.context = {"ssid": "OrgA"}
+        cs.full_clean()
+        cs.save()
+        c1.refresh_from_db()
+        c2.refresh_from_db()
+        with self.subTest("affected config changes to modified"):
+            self.assertEqual(c1.status, "modified")
+        with self.subTest("unaffected config remains applied"):
+            self.assertEqual(c2.status, "applied")
+
+    def test_status_update_on_group_variable_change(self):
+        org = self._get_org()
+        dg = self._create_device_group(organization=org, context={})
+        d1 = self._create_device(organization=org, group=dg)
+        c1 = self._create_config(device=d1)
+        c1.templates.add(
+            self._create_template(
+                name="t-with-var",
+                config={"interfaces": [{"name": "eth0", "type": "{{ ssid }}"}]},
+                default_values={"ssid": "default"},
+            )
+        )
+        c1.set_status_applied()
+        d2 = self._create_device(
+            organization=org, group=dg, name="d2", mac_address="00:11:22:33:44:56"
+        )
+        c2 = self._create_config(device=d2)
+        c2.set_status_applied()
+        dg.context = {"ssid": "OrgA"}
+        dg.full_clean()
+        dg.save()
+        c1.refresh_from_db()
+        c2.refresh_from_db()
+        with self.subTest("affected config changes to modified"):
+            self.assertEqual(c1.status, "modified")
+        with self.subTest("unaffected config remains applied"):
+            self.assertEqual(c2.status, "applied")
+
     def test_management_ip_changed_not_emitted_on_creation(self):
         with catch_signal(management_ip_changed) as handler:
             self._create_device(organization=self._get_org())