2342 display only benefits associated with the year of the sponsorshi…

…p package being edited (#2356)

* WIP

* WIP

* WIP

* we finally got there with the qs filter

* removing redundant tests

* removing unused imports

* missed one

sponsors/admin.py

@@ -246,9 +246,13 @@ def has_delete_permission(self, request, obj=None):
             return True
         return obj.open_for_editing
 
-    def get_queryset(self, *args, **kwargs):
-        qs = super().get_queryset(*args, **kwargs)
-        return qs.select_related("sponsorship_benefit__program", "program")
+    def get_queryset(self, request):
+        #filters the available benefits by the benefits for the year of the sponsorship
+        match = request.resolver_match
+        sponsorship = self.parent_model.objects.get(pk=match.kwargs["object_id"])
+        year = sponsorship.year
+
+        return super().get_queryset(request).filter(sponsorship_benefit__year=year)
 
 
 class TargetableEmailBenefitsFilter(admin.SimpleListFilter):