[tests] Fix deactivation test to exercise correct code path #1221

test_deactivation_fires_post_delete_signals was calling
device.config.templates.clear() directly without first setting the
config status to deactivating. This meant the per-instance delete
path guarded by is_deactivating_or_deactivated() in manage_vpn_clients
was never exercised, defeating the purpose of the regression test.

Replace templates.clear() with device.deactivate() which sets the
status to deactivating before clearing templates. Also replace the
conditional handler.assert_called() with an unconditional
handler.assert_called_once() and add an IP release assertion.
Remove unused variable cert (F841).

Related to #1221

Author: mn-ram

openwisp_controller/config/tests/test_vpn.py

@@ -887,7 +887,6 @@ def test_template_removal_fires_post_delete_signals(self):
         device, vpn, template = self._create_wireguard_vpn_template()
         vpn_client = device.config.vpnclient_set.first()
         self.assertIsNotNone(vpn_client)
-        cert = vpn_client.cert
         ip = vpn_client.ip
         self.assertIsNotNone(ip)
         initial_ip_count = IpAddress.objects.count()
@@ -907,9 +906,7 @@ def test_template_removal_fires_post_delete_signals(self):
             # For WireGuard there's no x509 cert to revoke, but the
             # post_delete handler should still have run without error.
             # The cert object should not exist anymore (CASCADE from VpnClient).
-            self.assertFalse(
-                VpnClient.objects.filter(pk=vpn_client.pk).exists()
-            )
+            self.assertFalse(VpnClient.objects.filter(pk=vpn_client.pk).exists())
 
     def test_deactivation_fires_post_delete_signals(self):
         """Regression test for #1221: deactivating a device must trigger
@@ -919,15 +916,15 @@ def test_deactivation_fires_post_delete_signals(self):
         initial_ip_count = IpAddress.objects.count()
 
         with catch_signal(vpn_peers_changed) as handler:
-            device.config.templates.clear()
-            # post_clear with deactivating state deletes vpn clients
-            # The signal should fire because per-instance delete is used
-            if device.config.vpnclient_set.count() == 0:
-                handler.assert_called()
+            device.deactivate()
+            handler.assert_called_once()
 
         # Verify cleanup happened
         self.assertEqual(device.config.vpnclient_set.count(), 0)
 
+        with self.subTest("IP address released"):
+            self.assertLess(IpAddress.objects.count(), initial_ip_count)
+
 
 class TestVxlan(BaseTestVpn, TestVxlanWireguardVpnMixin, TestCase):
     def test_vxlan_config_creation(self):