[#243] Fix expand query parameter

src/openklant/components/klantinteracties/api/tests/test_partijen.py

@@ -5,6 +5,8 @@
 from rest_framework import status
 from vng_api_common.tests import reverse
 
+from openklant.components.klantinteracties.models.constants import SoortPartij
+from openklant.components.klantinteracties.models.partijen import Partij
 from openklant.components.klantinteracties.models.tests.factories.digitaal_adres import (
     DigitaalAdresFactory,
 )
@@ -1797,6 +1799,49 @@ def test_destroy_partij(self):
         data = response.json()
         self.assertEqual(data["count"], 0)
 
+    def test_digitale_adressen_inclusion_param(self):
+        persoon = PersoonFactory(partij__soort_partij=SoortPartij.persoon)
+
+        persoon_with_adressen = PersoonFactory(partij__soort_partij=SoortPartij.persoon)
+        digitaal_adres = DigitaalAdresFactory(partij=persoon_with_adressen.partij)
+
+        def _get_detail_url(partij: Partij) -> str:
+            return reverse(
+                "klantinteracties:partij-detail", kwargs={"uuid": str(partij.uuid)}
+            )
+
+        # request the partij *without* any digitale adressen
+        response = self.client.get(
+            _get_detail_url(persoon.partij), data=dict(expand="digitaleAdressen")
+        )
+
+        self.assertEqual(response.status_code, status.HTTP_200_OK)
+
+        response_data: dict = response.json()
+
+        self.assertEqual(response_data["_expand"], {"digitaleAdressen": []})
+
+        # request the partij *with* digitale adressen
+        response = self.client.get(
+            _get_detail_url(persoon_with_adressen.partij),
+            data=dict(expand="digitaleAdressen"),
+        )
+
+        self.assertEqual(response.status_code, status.HTTP_200_OK)
+
+        response_data: dict = response.json()
+
+        received_adressen = response_data["_expand"]["digitaleAdressen"]
+        expected_url = reverse(
+            "klantinteracties:digitaaladres-detail",
+            kwargs=dict(uuid=digitaal_adres.uuid),
+        )
+
+        self.assertEqual(len(received_adressen), 1)
+        self.assertEqual(
+            received_adressen[0]["url"], f"http://testserver{expected_url}"
+        )
+
 
 class PartijIdentificatorTests(APITestCase):
     def test_list_partij_indetificator(self):

src/openklant/components/utils/expansion.py

@@ -64,16 +64,26 @@ def display_children(self) -> dict:
         return dict where children are grouped by their label
         """
         results = {}
+
         for child in self._children:
-            child_result = child.display()
-            if child.many:
-                results.setdefault(child.label, []).append(child_result)
-            else:
+            child_result: Optional[dict] = child.display()
+
+            if not child.many:
                 results[child.label] = child_result
+                continue
+
+            child_results: list = results.setdefault(child.label, [])
+
+            if child_result is None:
+                continue
+
+            if child_result is not None:
+                child_results.append(child_result)
+
         return results
 
-    def display(self) -> dict:
-        data = self.value.copy()
+    def display(self) -> Optional[dict]:
+        data = self.value.copy() if self.value is not None else None
         if self._children:
             data[EXPAND_KEY] = self.display_children()
         return data
@@ -111,6 +121,7 @@ def display_tree(self) -> dict:
 
         for node in root_nodes:
             result[node.id] = node.display_children()
+
         return result
 
 
@@ -168,15 +179,24 @@ def inclusions_dict(self, serializer: Serializer) -> dict:
         entries = self._inclusions((), serializer, serializer.instance)
 
         for obj, inclusion_serializer, parent, path, many in entries:
-            data = inclusion_serializer(instance=obj, context=serializer.context).data
-            tree.add_node(
-                id=data["url"],
-                value=data,
+            tree_kwargs = dict(
+                id=None,
+                value=None,
                 label=path[-1],
                 many=many,
                 parent_id=parent.get_absolute_api_url(request=request),
             )
 
+            if obj:
+                serializer = inclusion_serializer(
+                    instance=obj, context=serializer.context
+                )
+                data: dict | list = serializer.data
+
+                tree_kwargs.update(dict(value=data, id=data["url"]))
+
+            tree.add_node(**tree_kwargs)
+
         result = tree.display_tree()
 
         return result
@@ -204,11 +224,17 @@ def _field_inclusions(
         self,
         path: Tuple[str, ...],
         field: Field,
-        instance: models.Model,
+        instance: Optional[models.Model],
         name: str,
         inclusion_serializers: Dict[str, Union[str, Type[Serializer]]],
     ) -> Iterator[
-        Tuple[models.Model, Type[Serializer], models.Model, Tuple[str, ...], bool]
+        Tuple[
+            Optional[models.Model],
+            Type[Serializer],
+            models.Model,
+            Tuple[str, ...],
+            bool,
+        ]
     ]:
         """
         change return of this generator from (obj, serializer_class) to
@@ -237,6 +263,8 @@ def _field_inclusions(
             True if hasattr(field, "child_relation") else getattr(field, "many", False)
         )
 
+        obj: Optional[models.Model] = None
+
         for obj in self._some_related_field_inclusions(
             new_path, field, instance, inclusion_serializer
         ):
@@ -250,6 +278,9 @@ def _field_inclusions(
                 inclusion_serializers,
             ):
                 yield entry
+        else:
+            if new_path in self.allowed_paths:
+                yield obj, inclusion_serializer, instance, new_path, many
 
     def _some_related_field_inclusions(
         self,