[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 +1433,47 @@ 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 exposes correctly populated schema fields via drf-yasg.
+        """
+        try:
+            from drf_yasg import openapi
+            from drf_yasg.generators import OpenAPISchemaGenerator
+        except ImportError:
+            self.skipTest("drf-yasg is not installed")
+
+        info = openapi.Info(title="OpenWISP Monitoring API", default_version="v1")
+        generator = OpenAPISchemaGenerator(info=info)
+        schema = generator.get_schema(public=True)
+        schema_dict = schema.as_dict()
+
+        path_item = None
+        for path_name, path_obj in schema_dict.get("paths", {}).items():
+            if "monitoring/device/" in path_name and (
+                "{id}" in path_name or "{uuid}" in path_name
+            ):
+                path_item = path_obj
+                break
+
+        self.assertIsNotNone(path_item, "Device Metric API path not found in schema")
+        self.assertIn("get", path_item)
+
+        resp_200 = path_item["get"]["responses"].get("200")
+        self.assertIsNotNone(resp_200)
+        self.assertIn("schema", resp_200)
+
+        schema_obj = resp_200["schema"]
+        if "$ref" in schema_obj:
+            ref_path = schema_obj["$ref"]
+            definition_name = ref_path.split("/")[-1]
+            schema_obj = schema_dict.get("definitions", {}).get(definition_name, {})
+
+        self.assertIn("properties", schema_obj)
+        self.assertIn("mac_address", schema_obj["properties"])
+        self.assertIn("management_ip", schema_obj["properties"])
+
 
 class TestGeoApi(TestGeoMixin, AuthenticationMixin, DeviceMonitoringTestCase):
     location_model = Location