Merge pull request #1295 from Amsterdam/WON-65-AZA-Task-filter-bad-re…

…quest

prevent exception on no open tasks

app/apps/cases/views/case.py

@@ -174,7 +174,7 @@ class CaseFilter(filters.FilterSet):
         queryset=Tag.objects.all(), method="get_tag"
     )
     task = filters.ModelMultipleChoiceFilter(
-        queryset=CaseUserTask.objects.filter(completed=False),
+        queryset=CaseUserTask.objects.all(),
         method="get_task",
         to_field_name="task_name",
     )
@@ -294,6 +294,8 @@ def get_state_types(self, queryset, name, value):
         return queryset
 
     def get_task(self, queryset, name, value):
+        # Filter here instead of the queryset to prevent exceptions when there are no open tasks with a speciifc state
+        value = [task for task in value if not task.completed]
         if value:
             return queryset.filter(
                 workflows__completed=False,