it 'deletes all topics for the staggered deadline assignment and redirects to edit assignment page' do
      create(:topic, id: 30, assignment_id: 40, topic_identifier: 'E1740')
      create(:topic, id: 40, assignment_id: 40, topic_identifier: 'E1741')
      create(:topic, id: 50, assignment_id: 40, topic_identifier: 'E1742')
      request_params = { assignment_id: 40 }