it 'deletes all topics for the microtask assignment and redirects to edit assignment page' do
      create(:topic, id: 6000, assignment_id: 6000)
      create(:topic, id: 7000, assignment_id: 6000)
      request_params = { assignment_id: 6000 }
      post :delete_all_topics_for_assignment, params: request_params.merge(format: :html)