[fix] Fixed changed signals emitting on the creation of new device op…

…enwisp#649

Creating a new device object from the admin dashboard
emitted "device_group_changed" and "device_name_changed"
signals. The code for checking the values of changed fields
didn't take creating a device from admin into consideration.

Fixed the code that checks changed fields and added an
automated test for the same.

Closes openwisp#649

openwisp_controller/config/base/device.py

@@ -187,8 +187,13 @@ def save(self, *args, **kwargs):
                 self.key = KeyField.default_callable()
             else:
                 self.key = self.generate_key(shared_secret)
+        state_adding = self._state.adding
         super().save(*args, **kwargs)
-        self._check_changed_fields()
+        # The value of "self._state.adding" will always be "False"
+        # after performing the save operation. Hence, the actual value
+        # is stored in the "state_adding" variable.
+        if not state_adding:
+            self._check_changed_fields()
 
     def _check_changed_fields(self):
         self._get_initial_values_for_checked_fields()

openwisp_controller/config/tests/test_admin.py

@@ -10,10 +10,12 @@
 from swapper import load_model
 
 from openwisp_users.tests.utils import TestOrganizationMixin
+from openwisp_utils.tests import catch_signal
 
 from ...geo.tests.utils import TestGeoMixin
 from ...tests.utils import TestAdminMixin
 from .. import settings as app_settings
+from ..signals import device_group_changed, device_name_changed, management_ip_changed
 from .utils import (
     CreateConfigTemplateMixin,
     CreateDeviceGroupMixin,
@@ -36,6 +38,7 @@
 
 class TestAdmin(
     TestGeoMixin,
+    CreateDeviceGroupMixin,
     CreateConfigTemplateMixin,
     TestVpnX509Mixin,
     TestAdminMixin,
@@ -140,6 +143,25 @@ def test_add_device(self):
             device.config.templates.filter(name__in=['t1', 't2']).count(), 2
         )
 
+    def test_add_device_does_not_emit_changed_signals(self):
+        org1 = self._get_org()
+        path = reverse(f'admin:{self.app_label}_device_add')
+        data = self._get_device_params(org=org1)
+        data.update({'group': str(self._create_device_group().pk)})
+        self._login()
+        with catch_signal(
+            device_group_changed
+        ) as mocked_device_group_changed, catch_signal(
+            device_name_changed
+        ) as mocked_device_name_changed, catch_signal(
+            management_ip_changed
+        ) as mocked_management_ip_changed:
+            self.client.post(path, data)
+
+        mocked_device_group_changed.assert_not_called()
+        mocked_device_name_changed.assert_not_called()
+        mocked_management_ip_changed.assert_not_called()
+
     def test_preview_device(self):
         org = self._get_org()
         self._create_template(organization=org)

openwisp_controller/config/tests/test_device.py

@@ -389,8 +389,10 @@ def test_device_group_changed_emitted(self):
             )
 
     def test_device_group_changed_not_emitted_on_creation(self):
+        org = self._get_org()
+        device_group = self._create_device_group(organization=org)
         with catch_signal(device_group_changed) as handler:
-            self._create_device(organization=self._get_org())
+            self._create_device(name='test', organization=org, group=device_group)
         handler.assert_not_called()
 
     def test_device_field_changed_checks(self):