Ensure all elements exist before adding to the selection

arkindex/documents/api/elements.py

@@ -557,7 +557,7 @@ class ManageSelection(ListAPIView):
 
         elements = Element.objects.filter(id__in=request.data['ids']) \
             .prefetch_related('corpus', 'zone__image__server', 'type')
-        if not elements:
+        if elements.count() != len(set(request.data['ids'])):
             return Response(status=status.HTTP_404_NOT_FOUND)
         for corpus in Corpus.objects.filter(elements__in=elements).distinct():
             if Right.Read not in corpus.get_acl_rights(request.user):

arkindex/documents/tests/test_selection_api.py

@@ -42,7 +42,7 @@ class TestElementsAPI(FixtureAPITestCase):
         self.client.force_login(self.user)
         response = self.client.post(
             reverse('api:elements-selection'),
-            data={'ids': ['ffffffff-ffff-ffff-ffff-ffffffffffff']},
+            data={'ids': [self.vol.id, 'ffffffff-ffff-ffff-ffff-ffffffffffff']},
             format='json'
         )
         self.assertEqual(response.status_code, status.HTTP_404_NOT_FOUND)