fix: remove unrelated test and optimize query in _validate_owner_removal

- Remove test_update_feature_state__null_environment__returns_400
  (unrelated to this PR, should be a separate PR if fixing a bug)
- Only query existing owners when the corresponding ID set is non-empty
  to avoid unnecessary DB queries

Author: mimocode

api/features/views.py

@@ -487,16 +487,21 @@ def _validate_owner_removal(
         if not feature.project.enforce_feature_owners:
             return
 
-        existing_owner_ids = set(
-            feature.owners.values_list("id", flat=True)
-        )
-        existing_group_owner_ids = set(
-            feature.group_owners.values_list("id", flat=True)
+        actual_owners_to_remove = (
+            len(
+                owner_ids
+                & set(feature.owners.values_list("id", flat=True))
+            )
+            if owner_ids
+            else 0
         )
-
-        actual_owners_to_remove = len(owner_ids & existing_owner_ids)
-        actual_group_owners_to_remove = len(
-            group_owner_ids & existing_group_owner_ids
+        actual_group_owners_to_remove = (
+            len(
+                group_owner_ids
+                & set(feature.group_owners.values_list("id", flat=True))
+            )
+            if group_owner_ids
+            else 0
         )
 
         remaining = (

api/tests/unit/features/test_unit_features_views.py

@@ -3246,30 +3246,6 @@ def test_update_feature_state__change_feature__returns_400(
     )
 
 
-def test_update_feature_state__null_environment__returns_400(
-    admin_client_new: APIClient,
-    environment: Environment,
-    feature: Feature,
-    feature_state: FeatureState,
-) -> None:
-    # Given
-    url = reverse("api-v1:features:featurestates-detail", args=[feature_state.id])
-    data = {
-        "enabled": True,
-        "environment": None,
-        "feature": feature.id,
-    }
-
-    # When
-    response = admin_client_new.put(
-        url, data=json.dumps(data), content_type="application/json"
-    )
-
-    # Then
-    assert response.status_code == status.HTTP_400_BAD_REQUEST
-    assert "environment" in response.json()
-
-
 @pytest.mark.parametrize(
     "client",
     [lazy_fixture("admin_master_api_key_client"), lazy_fixture("admin_client")],