modidfy test PromotionServiceImplTest
modify PromotionServiceImpl inject PromotionDao
modify test should_return_75_when_input_productId
modify test DiscountPromotionTest
modify DiscountPromotion
modify PromotionFactory
modify App inject promotionService
modify CategoryDaoImpl
modify ProductDaoImpl
modify getPromotionTypes method
modify getDiscount method