Added an elementary unit test for CSP (#8340)
Added an elementary unit test for CSP (#8340)

* Added an elementary test case for CSP

* removed input

* Rename test file to avoid running in CI

* Fix YAPF error

* Remove one line function handler

PaddlePaddle/Paddle,luotao1/Paddle,jacquesqiao/Paddle,lcy-seso/Paddle,Canpio/Paddle,pkuyym/Paddle,jacquesqiao/Paddle,tensor-tang/Paddle,Canpio/Paddle,tensor-tang/Paddle,chengduoZH/Paddle,pkuyym/Paddle,luotao1/Paddle,QiJune/Paddle,baidu/Paddle,baidu/Paddle,luotao1/Paddle,putcn/Paddle,reyoung/Paddle,jacquesqiao/Paddle,putcn/Paddle,putcn/Paddle,baidu/Paddle,Canpio/Paddle,luotao1/Paddle,lcy-seso/Paddle,Canpio/Paddle,reyoung/Paddle,putcn/Paddle,lcy-seso/Paddle,QiJune/Paddle,pkuyym/Paddle,luotao1/Paddle,jacquesqiao/Paddle,Canpio/Paddle,Canpio/Paddle,QiJune/Paddle,luotao1/Paddle,PaddlePaddle/Paddle,lcy-seso/Paddle,QiJune/Paddle,tensor-tang/Paddle,reyoung/Paddle,baidu/Paddle,PaddlePaddle/Paddle,jacquesqiao/Paddle,chengduoZH/Paddle,PaddlePaddle/Paddle,baidu/Paddle,chengduoZH/Paddle,chengduoZH/Paddle,putcn/Paddle,chengduoZH/Paddle,tensor-tang/Paddle,lcy-seso/Paddle,putcn/Paddle,jacquesqiao/Paddle,Canpio/Paddle,QiJune/Paddle,PaddlePaddle/Paddle,reyoung/Paddle,pkuyym/Paddle,luotao1/Paddle,PaddlePaddle/Paddle,PaddlePaddle/Paddle,tensor-tang/Paddle,reyoung/Paddle,QiJune/Paddle,lcy-seso/Paddle,reyoung/Paddle,pkuyym/Paddle,pkuyym/Paddle,Canpio/Paddle