add validation to ItemCategorySerializer

src/tests/api/test_items.py

@@ -214,6 +214,44 @@ def test_category_update(token_client, organizer, event, team, category):
         assert ItemCategory.objects.get(pk=category.pk).name == {"en": "Test"}
 
 
+@pytest.mark.django_db
+def test_category_update_cross_selling_options(token_client, organizer, event, team, category):
+    resp = token_client.patch(
+        '/api/v1/organizers/{}/events/{}/categories/{}/'.format(organizer.slug, event.slug, category.pk),
+        {
+            "cross_selling_mode": "both",
+        },
+        format='json'
+    )
+    assert resp.status_code == 200
+    with scopes_disabled():
+        assert ItemCategory.objects.get(pk=category.pk).cross_selling_mode == 'both'
+
+    resp = token_client.patch(
+        '/api/v1/organizers/{}/events/{}/categories/{}/'.format(organizer.slug, event.slug, category.pk),
+        {
+            "cross_selling_mode": "something",
+        },
+        format='json'
+    )
+    assert resp.status_code == 400
+    with scopes_disabled():
+        assert ItemCategory.objects.get(pk=category.pk).cross_selling_mode == 'both'
+
+    resp = token_client.patch(
+        '/api/v1/organizers/{}/events/{}/categories/{}/'.format(organizer.slug, event.slug, category.pk),
+        {
+            "is_addon": True,
+        },
+        format='json'
+    )
+    assert resp.status_code == 400
+    assert 'mutually exclusive' in str(resp.data)
+    with scopes_disabled():
+        assert ItemCategory.objects.get(pk=category.pk).cross_selling_mode == 'both'
+        assert ItemCategory.objects.get(pk=category.pk).is_addon is False
+
+
 @pytest.mark.django_db
 def test_category_update_wrong_event(token_client, organizer, event2, category):
     resp = token_client.patch(