Add GraphQL support and API tests

docs/models/dcim/rackreservation.md

@@ -14,7 +14,7 @@ The rack unit or units being reserved. Multiple units can be expressed using com
 
 ### Total U's
 
-A calculated (read-only) field that reflects the total size of the range of units in the reservation. Can be filtered upon using `unit_count_min` and `unit_count_max` parameters in the UI or API.
+A calculated (read-only) field that reflects the total number of units in the reservation. Can be filtered upon using `unit_count_min` and `unit_count_max` parameters in the UI or API.
 
 ### Status
 

netbox/dcim/graphql/filters.py

@@ -997,6 +997,7 @@ class RackReservationFilter(TenancyFilterMixin, PrimaryModelFilter):
     units: Annotated['IntegerArrayLookup', strawberry.lazy('netbox.graphql.filter_lookups')] | None = (
         strawberry_django.filter_field()
     )
+    unit_count: ComparisonFilterLookup[int] | None = strawberry_django.filter_field()
     user: Annotated['UserFilter', strawberry.lazy('users.graphql.filters')] | None = strawberry_django.filter_field()
     user_id: ID | None = strawberry_django.filter_field()
     description: StrFilterLookup[str] | None = strawberry_django.filter_field()

netbox/dcim/graphql/types.py

@@ -2,6 +2,7 @@ from typing import TYPE_CHECKING, Annotated
 
 import strawberry
 import strawberry_django
+from django.db.models import Func, IntegerField
 
 from core.graphql.mixins import ChangelogMixin
 from dcim import models
@@ -803,6 +804,17 @@ class RackReservationType(PrimaryObjectType):
     tenant: Annotated["TenantType", strawberry.lazy('tenancy.graphql.types')] | None
     user: Annotated["UserType", strawberry.lazy('users.graphql.types')]
 
+    @classmethod
+    def get_queryset(cls, queryset, info, **kwargs):
+        queryset = super().get_queryset(queryset, info, **kwargs)
+        return queryset.annotate(
+            unit_count=Func('units', function='CARDINALITY', output_field=IntegerField())
+        )
+
+    @strawberry.field
+    def unit_count(self) -> int:
+        return len(self.units)
+
 
 @strawberry_django.type(
     models.RackRole,

netbox/dcim/tests/test_api.py

@@ -570,6 +570,15 @@ class RackReservationTest(APIViewTestCases.APIViewTestCase):
             },
         ]
 
+    def test_unit_count(self):
+        """unit_count should reflect the number of units in the reservation."""
+        url = reverse('dcim-api:rackreservation-list')
+        self.add_permissions('dcim.view_rackreservation')
+        response = self.client.get(url, **self.header)
+        self.assertHttpStatus(response, 200)
+        for result in response.data['results']:
+            self.assertEqual(result['unit_count'], len(result['units']))
+
 
 class ManufacturerTest(APIViewTestCases.APIViewTestCase):
     model = Manufacturer