[fix] Fix device metric API docs schema #716

Removed empty schema from DeviceMetricView that shadowed DRF auto-generated schema.

Fixes #716

Author: sargunn20

openwisp_monitoring/device/api/views.py

@@ -13,7 +13,7 @@
 from django.utils.translation import gettext_lazy as _
 from django_filters.rest_framework import DjangoFilterBackend
 from pytz import UTC
-from rest_framework import pagination, serializers, status
+from rest_framework import pagination, status
 from rest_framework.generics import (
     GenericAPIView,
     ListAPIView,

openwisp_monitoring/device/tests/test_api.py

@@ -1433,6 +1433,34 @@ def test_missing_tx_bytes(self):
         self.assertEqual(points[0].get("rx_bytes"), 324)
         self.assertEqual(points[0].get("tx_bytes"), 0)
 
+    def test_device_metric_view_schema_not_empty(self):
+        """
+        Regression test for https://github.com/openwisp/openwisp-monitoring/issues/716.
+        Ensures DeviceMetricView uses a proper serializer (not blank)
+        and does not shadow DRF's schema attribute with a plain dict.
+        """
+        from ..api.serializers import MonitoringDeviceDetailSerializer
+        from ..api.views import DeviceMetricView
+
+        # serializer_class must be the concrete serializer, not blank
+        self.assertIs(
+            DeviceMetricView.serializer_class,
+            MonitoringDeviceDetailSerializer,
+        )
+        # Serializer must expose real fields
+        fields = MonitoringDeviceDetailSerializer().get_fields()
+        self.assertTrue(len(fields) > 0, "Serializer should declare fields")
+        for expected in ("id", "name", "monitoring"):
+            self.assertIn(expected, fields)
+        # The view must NOT shadow DRF's schema with a plain dict
+        schema_attr = getattr(DeviceMetricView, "schema", None)
+        if schema_attr is not None:
+            self.assertFalse(
+                isinstance(schema_attr, dict),
+                "DeviceMetricView.schema must not be a plain dict; "
+                "it would shadow DRF's APIView.schema and break API docs.",
+            )
+
 
 class TestGeoApi(TestGeoMixin, AuthenticationMixin, DeviceMonitoringTestCase):
     location_model = Location