it 'create topic and delete_all_selected_topics for not a staggered deadline assignment and redirects to edit assignment page with single topic selected' do
      create(:topic, id: 30, assignment_id: 30, topic_identifier: 'E1734')
      request_params = { assignment_id: 30, topic_ids: ['E1734'] }
      post :delete_all_selected_topics, params: request_params
      expect(flash[:success]).to eq('All selected topics have been deleted successfully.')