fix memory leak in unit test
fix memory leak in unit test

ShuxinLin/peloton,jessesleeping/iso_peloton,apavlo/peloton,jessesleeping/iso_peloton,AllisonWang/peloton,wangziqi2016/peloton,AngLi-Leon/peloton,vittvolt/peloton,AllisonWang/peloton,AngLi-Leon/peloton,vittvolt/15721-peloton,malin1993ml/peloton,haojin2/peloton,eric-haibin-lin/peloton-1,malin1993ml/peloton,prashasthip/peloton,malin1993ml/peloton,vittvolt/15721-peloton,prashasthip/peloton,AllisonWang/peloton,phisiart/peloton-p3,yingjunwu/peloton,ShuxinLin/peloton,phisiart/peloton-p3,wangziqi2016/peloton,PauloAmora/peloton,phisiart/peloton-p3,cmu-db/peloton,haojin2/peloton,cmu-db/peloton,seojungmin/peloton,seojungmin/peloton,malin1993ml/peloton,eric-haibin-lin/peloton-1,PauloAmora/peloton,wangziqi2016/peloton,phisiart/peloton-p3,ShuxinLin/peloton,AngLi-Leon/peloton,jessesleeping/iso_peloton,vittvolt/15721-peloton,PauloAmora/peloton,AllisonWang/peloton,vittvolt/peloton,ShuxinLin/peloton,eric-haibin-lin/peloton-1,eric-haibin-lin/peloton-1,apavlo/peloton,wangziqi2016/peloton,yingjunwu/peloton,ShuxinLin/peloton,vittvolt/peloton,malin1993ml/peloton,vittvolt/15721-peloton,cmu-db/peloton,vittvolt/15721-peloton,eric-haibin-lin/peloton-1,haojin2/peloton,seojungmin/peloton,prashasthip/peloton,haojin2/peloton,apavlo/peloton,PauloAmora/peloton,AngLi-Leon/peloton,eric-haibin-lin/peloton-1,PauloAmora/peloton,yingjunwu/peloton,vittvolt/15721-peloton,jessesleeping/iso_peloton,AllisonWang/peloton,wangziqi2016/peloton,jessesleeping/iso_peloton,yingjunwu/peloton,prashasthip/peloton,cmu-db/peloton,AngLi-Leon/peloton,ShuxinLin/peloton,jessesleeping/iso_peloton,prashasthip/peloton,malin1993ml/peloton,phisiart/peloton-p3,cmu-db/peloton,jessesleeping/iso_peloton,AngLi-Leon/peloton,vittvolt/peloton,seojungmin/peloton,apavlo/peloton,phisiart/peloton-p3,vittvolt/peloton,vittvolt/peloton,haojin2/peloton,seojungmin/peloton,apavlo/peloton,apavlo/peloton,wangziqi2016/peloton,yingjunwu/peloton,PauloAmora/peloton,yingjunwu/peloton,prashasthip/peloton,AllisonWang/peloton,haojin2/peloton,cmu-db/peloton,seojungmin/peloton