[chores] Minor improvements

openwisp_controller/subnet_division/base/models.py

@@ -71,6 +71,7 @@ def rule_class(self):
     def clean(self):
         super().clean()
         self._validate_label()
+        self._validate_master_subnet_validity()
         self._validate_master_subnet_consistency()
         self._validate_ip_address_consistency()
         if not self._state.adding:
@@ -86,6 +87,10 @@ def _validate_label(self):
                 }
             )
 
+    def _validate_master_subnet_validity(self):
+        if not self.master_subnet.subnet:
+            raise ValidationError({'master_subnet': _('Invalid master subnet.')})
+
     def _validate_existing_fields(self):
         db_instance = self._meta.model.objects.get(id=self.id)
         # The size field should not be changed
@@ -103,15 +108,11 @@ def _validate_existing_fields(self):
             )
 
     def _validate_master_subnet_consistency(self):
-        # Try to retrieve and validate master_subnet
         master_subnet = self.master_subnet.subnet
-        if not master_subnet:
-            raise ValidationError(
-                {'master_subnet': _('Master subnet is required and cannot be empty.')}
-            )
         # Try to generate subnets and validate size
         try:
             next(master_subnet.subnets(new_prefix=self.size))
+        # if size is not consistent, raise error
         except ValueError:
             raise ValidationError(
                 {
@@ -122,7 +123,6 @@ def _validate_master_subnet_consistency(self):
                     )
                 }
             )
-
         # Ensure that master subnet can accommodate
         # the required number of generated subnets
         available = 2 ** (self.size - master_subnet.prefixlen)
@@ -139,7 +139,6 @@ def _validate_master_subnet_consistency(self):
                     )
                 }
             )
-
         # Validate organization of master subnet
         if (
             self.master_subnet.organization is not None

openwisp_controller/subnet_division/tests/test_models.py

@@ -988,7 +988,7 @@ def test_invalid_master_subnet(self):
             rule.full_clean()
         e = cm.exception
         self.assertIn(
-            'Master subnet must be a valid subnet.',
+            'Invalid master subnet.',
             e.message_dict.get('master_subnet', []),
         )