Prioritize related institutions in autocomplete.

The autocomplete endpoint accepts an optional `case` parameter.
The backend will put institutions related to `case` on top of the
suggestions list.

backend-project/small_eod/autocomplete/tests/test_views.py

@@ -98,6 +98,24 @@ def validate_item(self, item):
         self.assertEqual(item["id"], self.obj.id)
         self.assertEqual(item["name"], self.obj.name)
 
+    def test_suggests_related(self):
+        institution_a = InstitutionFactory(name="institution_a")
+        institution_b = InstitutionFactory(name="institution_b")
+        InstitutionFactory(name="institution_c")
+
+        # Make the case audit the 2nd institution - it's unlikely to appear
+        # at the top of the results just by coincidence.
+        case = CaseFactory(audited_institutions=[institution_b])
+
+        # Match all - the related institution should appear at the top.
+        resp = self.get_response_for_query("institution", case=case.id)
+        self.assertEqual(resp.data['results'][0]['id'], institution_b.id)
+
+        # Match a specific, non-related item.
+        # The related institution should not be present.
+        resp = self.get_response_for_query("institution_a", case=case.id)
+        self.assertEqual([r['id'] for r in resp.data['results']], [institution_a.id])
+
 
 class TagAutocompleteViewSetTestCase(ReadOnlyViewSetMixin, SearchQueryMixin, TestCase):
     basename = "autocomplete_tag"

backend-project/small_eod/autocomplete/views.py

@@ -1,4 +1,5 @@
 from django_filters.rest_framework import DjangoFilterBackend
+from django.db import models
 from rest_framework import viewsets
 
 from ..administrative_units.filterset import AdministrativeUnitFilterSet
@@ -32,7 +33,6 @@
     UserAutocompleteSerializer,
 )
 
-
 class AdministrativeUnitAutocompleteViewSet(viewsets.ReadOnlyModelViewSet):
     queryset = AdministrativeUnit.objects.only("id", "name").all()
     serializer_class = AdministrativeUnitAutocompleteSerializer
@@ -83,11 +83,26 @@ class FeatureOptionAutocompleteViewSet(viewsets.ReadOnlyModelViewSet):
 
 
 class InstitutionAutocompleteViewSet(viewsets.ReadOnlyModelViewSet):
-    queryset = Institution.objects.only("id", "name").all()
     serializer_class = InstitutionAutocompleteSerializer
     filter_backends = (DjangoFilterBackend,)
     filterset_class = InstitutionFilterSet
 
+    def get_queryset(self):
+        req = self.request
+        related_case_id = req.GET.get('case', None)
+        if related_case_id is None:
+            qs = Institution.objects.all()
+        else:
+            # Put related institutions at the beginning of the list.
+            qs = Institution.objects.annotate(
+                related=models.Case(
+                    models.When(case=related_case_id, then=True),
+                    default=False,
+                    output_field=models.BooleanField()
+                )
+            ).order_by('-related')
+        return qs.only("id", "name")
+
 
 class TagAutocompleteViewSet(viewsets.ReadOnlyModelViewSet):
     queryset = Tag.objects.only("id", "name").all()

backend-project/small_eod/search/tests/mixins.py

@@ -1,9 +1,9 @@
 class SearchQueryMixin:
-    def get_response_for_query(self, query):
+    def get_response_for_query(self, query, **data):
         self.login_required()
         return self.client.get(
             self.get_url(name="list", **self.get_extra_kwargs()),
-            data={"query": query},
+            data={"query": query, **data},
         )
 
     def assertResultEqual(self, response, items):