add ut for pipe enhancement
add ut for pipe enhancement

rednaxelafx/apache-spark,aray/spark,ConeyLiu/spark,zuotingbing/spark,ioana-delaney/spark,witgo/spark,big-pegasus/spark,publicRoman/spark,shaneknapp/spark,jrshust/spark,highfei2011/spark,szhem/spark,ron8hu/spark,minixalpha/spark,pronix/spark,actuaryzhang/spark,bdrillard/spark,milliman/spark,rekhajoshm/spark,cloud-fan/spark,witgo/spark,poffuomo/spark,poffuomo/spark,wangyum/spark,MLnick/spark,huang1900/spark,wangmiao1981/spark,Aegeaner/spark,mike0sv/spark,zzcclp/spark,saltstar/spark,ahnqirage/spark,alunarbeach/spark,janewangfb/spark,szhem/spark,1haodian/spark,bravo-zhang/spark,UndeadBaneGitHub/spark,lxsmnv/spark,dhruve/spark,xflin/spark,rikima/spark,caneGuy/spark,tejasapatil/spark,liutang123/spark,mike0sv/spark,dongjoon-hyun/spark,akopich/spark,aosagie/spark,mahak/spark,spark-test/spark,xflin/spark,BryanCutler/spark,guoxiaolongzte/spark,andrewor14/iolap,ibm-research-ireland/sparkoscope,yanboliang/spark,esi-mineset/spark,kissmetrics/spark,rikima/spark,andrewor14/spark,cin/spark,JerryLead/spark,ericvandenbergfb/spark,mzl9039/spark,ConeyLiu/spark,jlopezmalla/spark,publicRoman/spark,WeichenXu123/spark,saltstar/spark,xuanyuanking/spark,SHASHANKB/spark,ibm-research-ireland/sparkoscope,icexelloss/spark,saturday-shi/spark,esi-mineset/spark,xflin/spark,apache/spark,wangyum/spark,BryanCutler/spark,patrick-nicholson/spark,skonto/spark,spark-test/spark,cin/spark,srowen/spark,apache/spark,xuanyuanking/spark,debugger87/spark,stanzhai/spark,bravo-zhang/spark,mzl9039/spark,shubhamchopra/spark,saturday-shi/spark,wzhfy/spark,eyalfa/spark,dbtsai/spark,byakuinss/spark,JoshRosen/spark,skonto/spark,panfengfeng/spark,kissmetrics/spark,ajaysaini725/spark,poffuomo/spark,jianran/spark,jlopezmalla/spark,mike0sv/spark,ericvandenbergfb/spark,akopich/spark,stanzhai/spark,WindCanDie/spark,huang1900/spark,patrick-nicholson/spark,zero323/spark,gengliangwang/spark,kimoonkim/spark,xflin/spark,wangyum/spark,big-pegasus/spark,LantaoJin/spark,apache-spark-on-k8s/spark,ConeyLiu/spark,xflin/spark,mike0sv/spark,nlalevee/spark,aosagie/spark,srowen/spark,srowen/spark,poffuomo/spark,ahnqirage/spark,zhouyejoe/spark,hhbyyh/spark,pronix/spark,nlalevee/spark,xuanyuanking/spark,liyichao/spark,yanboliang/spark,dbtsai/spark,vinodkc/spark,vinodkc/spark,tejasapatil/spark,liutang123/spark,adrian-ionescu/apache-spark,cloud-fan/spark,andrewor14/iolap,cin/spark,markhamstra/spark,caneGuy/spark,cloudera/spark,srowen/spark,vax11780/spark,mzl9039/spark,narahari92/spark,shubhamchopra/spark,jrshust/spark,mkolod/incubator-spark,sahilTakiar/spark,huang1900/spark,Panos-Bletsos/spark-cost-model-optimizer,liutang123/spark,janewangfb/spark,rednaxelafx/apache-spark,ahnqirage/spark,cloudera/spark,yanboliang/spark,witgo/spark,wzhfy/spark,JoshRosen/spark,facaiy/spark,apache-spark-on-k8s/spark,ptkool/spark,setjet/spark,rednaxelafx/apache-spark,hvanhovell/spark,aray/spark,minixalpha/spark,saturday-shi/spark,witgo/spark,rekhajoshm/spark,publicRoman/spark,goldmedal/spark,kevinyu98/spark,SnappyDataInc/spark,kimoonkim/spark,brad-kaiser/spark,nilsgrabbert/spark,joseph-torres/spark,ajaysaini725/spark,SnappyDataInc/spark,kevinyu98/spark,liutang123/spark,taroplus/spark,skonto/spark,liutang123/spark,jlopezmalla/spark,ahnqirage/spark,holdenk/spark,milliman/spark,tejasapatil/spark,brad-kaiser/spark,lyogavin/spark,techaddict/spark,ioana-delaney/spark,yanboliang/spark,jianran/spark,yanboliang/spark,big-pegasus/spark,metamx/spark,minixalpha/spark,zhouyejoe/spark,ron8hu/spark,Aegeaner/spark,rezasafi/spark,LantaoJin/spark,dongjoon-hyun/spark,tengpeng/spark,vinodkc/spark,goldmedal/spark,akopich/spark,guoxiaolongzte/spark,big-pegasus/spark,panfengfeng/spark,JoshRosen/spark,darionyaphet/spark,big-pegasus/spark,dbtsai/spark,zhouyejoe/spark,1haodian/spark,chuckchen/spark,LantaoJin/spark,ioana-delaney/spark,shaneknapp/spark,dongjoon-hyun/spark,setjet/spark,bOOm-X/spark,WeichenXu123/spark,huang1900/spark,zero323/spark,someorz/spark,mdespriee/spark,bOOm-X/spark,jlopezmalla/spark,bravo-zhang/spark,shaneknapp/spark,nchammas/spark,Aegeaner/spark,janewangfb/spark,UndeadBaneGitHub/spark,dhruve/spark,witgo/spark,setjet/spark,kimoonkim/spark,ron8hu/spark,vax11780/spark,vax11780/spark,Panos-Bletsos/spark-cost-model-optimizer,facaiy/spark,spark-test/spark,rjpower/spark,alunarbeach/spark,ddna1021/spark,kiszk/spark,metamx/spark,patrick-nicholson/spark,ueshin/apache-spark,sachintyagi22/spark,alunarbeach/spark,nchammas/spark,hvanhovell/spark,ajaysaini725/spark,rekhajoshm/spark,loneknightpy/spark,SHASHANKB/spark,gioenn/xSpark,alunarbeach/spark,eyalfa/spark,wzhfy/spark,nilsgrabbert/spark,brad-kaiser/spark,facaiy/spark,andrewor14/spark,sryza/spark,ajaysaini725/spark,pronix/spark,mzl9039/spark,nlalevee/spark,patrick-nicholson/spark,zhouyejoe/spark,ibm-research-ireland/sparkoscope,jkbradley/spark,rezasafi/spark,hvanhovell/spark,darionyaphet/spark,WeichenXu123/spark,ueshin/apache-spark,rikima/spark,highfei2011/spark,highfei2011/spark,andrewor14/spark,nilsgrabbert/spark,cloud-fan/spark,joseph-torres/spark,someorz/spark,dotunolafunmiloye/spark,actuaryzhang/spark,darionyaphet/spark,SnappyDataInc/spark,rednaxelafx/apache-spark,setjet/spark,rjpower/spark,jkbradley/spark,sahilTakiar/spark,icexelloss/spark,joseph-torres/spark,vax11780/spark,1haodian/spark,saltstar/spark,maropu/spark,techaddict/spark,wzhfy/spark,dongjoon-hyun/spark,apache-spark-on-k8s/spark,srowen/spark,icexelloss/spark,poffuomo/spark,gengliangwang/spark,guoxiaolongzte/spark,chuckchen/spark,byakuinss/spark,setjet/spark,mahak/spark,actuaryzhang/spark,narahari92/spark,apache/spark,eyalfa/spark,brad-kaiser/spark,andrewor14/spark,WindCanDie/spark,lyogavin/spark,zzcclp/spark,setjet/spark,lxsmnv/spark,gioenn/xSpark,zzcclp/spark,cin/spark,tengpeng/spark,map222/spark,hhbyyh/spark,facaiy/spark,loneknightpy/spark,aokolnychyi/spark,akopich/spark,aokolnychyi/spark,byakuinss/spark,Panos-Bletsos/spark-cost-model-optimizer,aokolnychyi/spark,xuanyuanking/spark,actuaryzhang/spark,publicRoman/spark,lxsmnv/spark,mdespriee/spark,bdrillard/spark,narahari92/spark,huang1900/spark,publicRoman/spark,kevinyu98/spark,ron8hu/spark,sachintyagi22/spark,cloud-fan/spark,shuangshuangwang/spark,jianran/spark,minixalpha/spark,WindCanDie/spark,ioana-delaney/spark,someorz/spark,janewangfb/spark,minixalpha/spark,HyukjinKwon/spark,narahari92/spark,wgpshashank/spark,rekhajoshm/spark,shaneknapp/spark,darionyaphet/spark,cin/spark,byakuinss/spark,metamx/spark,ioana-delaney/spark,zuotingbing/spark,ueshin/apache-spark,MLnick/spark,aokolnychyi/spark,MLnick/spark,taroplus/spark,tejasapatil/spark,1haodian/spark,metamx/spark,debugger87/spark,adrian-ionescu/apache-spark,publicRoman/spark,goldmedal/spark,wzhfy/spark,milliman/spark,gioenn/xSpark,JoshRosen/spark,rjpower/spark,ConeyLiu/spark,jianran/spark,hhbyyh/spark,ron8hu/spark,mzl9039/spark,michalsenkyr/spark,LantaoJin/spark,caneGuy/spark,ericvandenbergfb/spark,brad-kaiser/spark,rekhajoshm/spark,wangyum/spark,janewangfb/spark,stanzhai/spark,maropu/spark,minixalpha/spark,SHASHANKB/spark,guoxiaolongzte/spark,markhamstra/spark,nlalevee/spark,gengliangwang/spark,zhouyejoe/spark,sachintyagi22/spark,dotunolafunmiloye/spark,bdrillard/spark,mzl9039/spark,icexelloss/spark,SHASHANKB/spark,vinodkc/spark,stanzhai/spark,zuotingbing/spark,lxsmnv/spark,zzcclp/spark,tejasapatil/spark,lyogavin/spark,szhem/spark,ajaysaini725/spark,sureshthalamati/spark,ueshin/apache-spark,yanboliang/spark,aray/spark,pgandhi999/spark,mike0sv/spark,akopich/spark,UndeadBaneGitHub/spark,techaddict/spark,bOOm-X/spark,huang1900/spark,sureshthalamati/spark,andrewor14/iolap,zero323/spark,loneknightpy/spark,UndeadBaneGitHub/spark,dhruve/spark,michalsenkyr/spark,matthewfranglen/spark,mahak/spark,bravo-zhang/spark,bdrillard/spark,darionyaphet/spark,eyalfa/spark,MLnick/spark,highfei2011/spark,bdrillard/spark,wgpshashank/spark,icexelloss/spark,zero323/spark,jrshust/spark,mzl9039/spark,cloud-fan/spark,JerryLead/spark,taroplus/spark,vinodkc/spark,haowu80s/spark,sahilTakiar/spark,hhbyyh/spark,kissmetrics/spark,rezasafi/spark,esi-mineset/spark,skonto/spark,narahari92/spark,Panos-Bletsos/spark-cost-model-optimizer,shuangshuangwang/spark,haowu80s/spark,michalsenkyr/spark,nchammas/spark,ptkool/spark,Aegeaner/spark,ddna1021/spark,nilsgrabbert/spark,wgpshashank/spark,saturday-shi/spark,nchammas/spark,jianran/spark,aray/spark,maropu/spark,spark-test/spark,wangyum/spark,markhamstra/spark,ConeyLiu/spark,jkbradley/spark,ibm-research-ireland/sparkoscope,jkbradley/spark,haowu80s/spark,eyalfa/spark,brad-kaiser/spark,eyalfa/spark,ptkool/spark,rjpower/spark,HyukjinKwon/spark,ajaysaini725/spark,pronix/spark,dhruve/spark,poffuomo/spark,cloud-fan/spark,lvdongr/spark,Panos-Bletsos/spark-cost-model-optimizer,metamx/spark,gioenn/xSpark,mahak/spark,cloud-fan/spark,Panos-Bletsos/spark-cost-model-optimizer,aokolnychyi/spark,joseph-torres/spark,byakuinss/spark,patrick-nicholson/spark,ibm-research-ireland/sparkoscope,rednaxelafx/apache-spark,zzcclp/spark,apache/spark,vinodkc/spark,holdenk/spark,ibm-research-ireland/sparkoscope,jiangxb1987/spark,rezasafi/spark,cin/spark,stanzhai/spark,skonto/spark,xuanyuanking/spark,ptkool/spark,adrian-ionescu/apache-spark,maropu/spark,wangyum/spark,techaddict/spark,someorz/spark,debugger87/spark,facaiy/spark,holdenk/spark,ahnqirage/spark,mahak/spark,nilsgrabbert/spark,michalsenkyr/spark,mkolod/incubator-spark,HyukjinKwon/spark,BryanCutler/spark,jiangxb1987/spark,wzhfy/spark,WindCanDie/spark,narahari92/spark,panfengfeng/spark,wangmiao1981/spark,janewangfb/spark,JerryLead/spark,byakuinss/spark,akopich/spark,dongjoon-hyun/spark,ericvandenbergfb/spark,goldmedal/spark,jkbradley/spark,lvdongr/spark,sahilTakiar/spark,JerryLead/spark,wangmiao1981/spark,kissmetrics/spark,andrewor14/iolap,gengliangwang/spark,1haodian/spark,sureshthalamati/spark,MLnick/spark,nchammas/spark,michalsenkyr/spark,Aegeaner/spark,adrian-ionescu/apache-spark,BryanCutler/spark,rezasafi/spark,SHASHANKB/spark,esi-mineset/spark,panfengfeng/spark,icexelloss/spark,shubhamchopra/spark,minixalpha/spark,kiszk/spark,mdespriee/spark,nilsgrabbert/spark,ioana-delaney/spark,1haodian/spark,rezasafi/spark,caneGuy/spark,hvanhovell/spark,tejasapatil/spark,Aegeaner/spark,map222/spark,saturday-shi/spark,xflin/spark,tengpeng/spark,markhamstra/spark,mdespriee/spark,andrewor14/iolap,spark-test/spark,saltstar/spark,jiangxb1987/spark,SHASHANKB/spark,xflin/spark,ericvandenbergfb/spark,panfengfeng/spark,witgo/spark,pgandhi999/spark,mdespriee/spark,markhamstra/spark,ahnqirage/spark,1haodian/spark,shuangshuangwang/spark,map222/spark,markhamstra/spark,sureshthalamati/spark,debugger87/spark,ioana-delaney/spark,publicRoman/spark,xuanyuanking/spark,adrian-ionescu/apache-spark,apache-spark-on-k8s/spark,pgandhi999/spark,MLnick/spark,someorz/spark,pronix/spark,rednaxelafx/apache-spark,poffuomo/spark,joseph-torres/spark,guoxiaolongzte/spark,holdenk/spark,kimoonkim/spark,jlopezmalla/spark,zuotingbing/spark,ddna1021/spark,wzhfy/spark,milliman/spark,mkolod/incubator-spark,shuangshuangwang/spark,nlalevee/spark,maropu/spark,aokolnychyi/spark,WeichenXu123/spark,loneknightpy/spark,liutang123/spark,bdrillard/spark,spark-test/spark,HyukjinKwon/spark,dbtsai/spark,HyukjinKwon/spark,saltstar/spark,sachintyagi22/spark,cloudera/spark,jiangxb1987/spark,rikima/spark,bOOm-X/spark,hhbyyh/spark,dbtsai/spark,UndeadBaneGitHub/spark,SnappyDataInc/spark,bOOm-X/spark,alunarbeach/spark,taroplus/spark,dhruve/spark,Aegeaner/spark,lvdongr/spark,wangmiao1981/spark,kimoonkim/spark,zhouyejoe/spark,WeichenXu123/spark,JerryLead/spark,tejasapatil/spark,zzcclp/spark,bOOm-X/spark,taroplus/spark,markhamstra/spark,nchammas/spark,dotunolafunmiloye/spark,JoshRosen/spark,tengpeng/spark,SnappyDataInc/spark,vinodkc/spark,sahilTakiar/spark,JerryLead/spark,byakuinss/spark,esi-mineset/spark,big-pegasus/spark,aray/spark,ericvandenbergfb/spark,sryza/spark,stanzhai/spark,metamx/spark,SnappyDataInc/spark,pgandhi999/spark,ptkool/spark,shubhamchopra/spark,gengliangwang/spark,Panos-Bletsos/spark-cost-model-optimizer,janewangfb/spark,liyichao/spark,lyogavin/spark,stanzhai/spark,WeichenXu123/spark,cloudera/spark,WindCanDie/spark,andrewor14/spark,zuotingbing/spark,tengpeng/spark,apache-spark-on-k8s/spark,JoshRosen/spark,jkbradley/spark,lyogavin/spark,aray/spark,mdespriee/spark,rekhajoshm/spark,wangyum/spark,bravo-zhang/spark,rjpower/spark,kevinyu98/spark,SHASHANKB/spark,ddna1021/spark,liyichao/spark,map222/spark,aosagie/spark,jrshust/spark,eyalfa/spark,holdenk/spark,gioenn/xSpark,ibm-research-ireland/sparkoscope,zhouyejoe/spark,bOOm-X/spark,zero323/spark,andrewor14/iolap,kiszk/spark,guoxiaolongzte/spark,andrewor14/spark,BryanCutler/spark,maropu/spark,ueshin/apache-spark,hhbyyh/spark,actuaryzhang/spark,panfengfeng/spark,kissmetrics/spark,jrshust/spark,skonto/spark,tengpeng/spark,facaiy/spark,liyichao/spark,UndeadBaneGitHub/spark,goldmedal/spark,liutang123/spark,ueshin/apache-spark,huang1900/spark,saltstar/spark,milliman/spark,loneknightpy/spark,actuaryzhang/spark,liyichao/spark,dhruve/spark,akopich/spark,highfei2011/spark,WindCanDie/spark,jrshust/spark,kiszk/spark,sachintyagi22/spark,milliman/spark,BryanCutler/spark,lxsmnv/spark,shuangshuangwang/spark,goldmedal/spark,sryza/spark,taroplus/spark,spark-test/spark,apache/spark,ddna1021/spark,holdenk/spark,ddna1021/spark,lvdongr/spark,bdrillard/spark,saturday-shi/spark,shubhamchopra/spark,patrick-nicholson/spark,patrick-nicholson/spark,lvdongr/spark,metamx/spark,ConeyLiu/spark,debugger87/spark,apache/spark,mahak/spark,highfei2011/spark,liyichao/spark,jrshust/spark,ron8hu/spark,kissmetrics/spark,rikima/spark,jkbradley/spark,adrian-ionescu/apache-spark,caneGuy/spark,skonto/spark,mike0sv/spark,zuotingbing/spark,milliman/spark,szhem/spark,lvdongr/spark,joseph-torres/spark,kiszk/spark,zero323/spark,shuangshuangwang/spark,goldmedal/spark,ptkool/spark,ddna1021/spark,ron8hu/spark,shaneknapp/spark,wangmiao1981/spark,alunarbeach/spark,big-pegasus/spark,srowen/spark,jianran/spark,WeichenXu123/spark,chuckchen/spark,shaneknapp/spark,lxsmnv/spark,lxsmnv/spark,gengliangwang/spark,someorz/spark,LantaoJin/spark,caneGuy/spark,kiszk/spark,cin/spark,rezasafi/spark,JerryLead/spark,aosagie/spark,pgandhi999/spark,aosagie/spark,gioenn/xSpark,liyichao/spark,hvanhovell/spark,kevinyu98/spark,rekhajoshm/spark,adrian-ionescu/apache-spark,sryza/spark,joseph-torres/spark,nilsgrabbert/spark,UndeadBaneGitHub/spark,apache-spark-on-k8s/spark,dotunolafunmiloye/spark,loneknightpy/spark,rednaxelafx/apache-spark,panfengfeng/spark,vax11780/spark,ericvandenbergfb/spark,kevinyu98/spark,ahnqirage/spark,haowu80s/spark,sureshthalamati/spark,wangmiao1981/spark,chuckchen/spark,kevinyu98/spark,narahari92/spark,chuckchen/spark,jlopezmalla/spark,haowu80s/spark,saturday-shi/spark,caneGuy/spark,aosagie/spark,shuangshuangwang/spark,kimoonkim/spark,darionyaphet/spark,shubhamchopra/spark,andrewor14/spark,someorz/spark,actuaryzhang/spark,mdespriee/spark,BryanCutler/spark,ptkool/spark,HyukjinKwon/spark,cloudera/spark,taroplus/spark,sahilTakiar/spark,darionyaphet/spark,sureshthalamati/spark,holdenk/spark,dbtsai/spark,szhem/spark,sahilTakiar/spark,LantaoJin/spark,jiangxb1987/spark,jianran/spark,szhem/spark,szhem/spark,dbtsai/spark,zzcclp/spark,icexelloss/spark,techaddict/spark,mike0sv/spark,jiangxb1987/spark,andrewor14/iolap,mkolod/incubator-spark,aokolnychyi/spark,LantaoJin/spark,map222/spark,map222/spark,MLnick/spark,srowen/spark,shubhamchopra/spark,apache-spark-on-k8s/spark,dhruve/spark,xuanyuanking/spark,kiszk/spark,pgandhi999/spark,gioenn/xSpark,haowu80s/spark,pronix/spark,facaiy/spark,map222/spark,witgo/spark,sachintyagi22/spark,jlopezmalla/spark,jiangxb1987/spark,SnappyDataInc/spark,kimoonkim/spark,michalsenkyr/spark,bravo-zhang/spark,aosagie/spark,shaneknapp/spark,loneknightpy/spark,sryza/spark,debugger87/spark,HyukjinKwon/spark,michalsenkyr/spark,mahak/spark,sachintyagi22/spark,chuckchen/spark,rikima/spark,zuotingbing/spark,gengliangwang/spark,pgandhi999/spark,esi-mineset/spark,chuckchen/spark,dongjoon-hyun/spark,WindCanDie/spark,nlalevee/spark,ueshin/apache-spark,saltstar/spark,esi-mineset/spark,yanboliang/spark,guoxiaolongzte/spark,ajaysaini725/spark,maropu/spark,brad-kaiser/spark,wgpshashank/spark,tengpeng/spark,apache/spark,techaddict/spark,zero323/spark,hhbyyh/spark,JoshRosen/spark,hvanhovell/spark,debugger87/spark,nlalevee/spark,setjet/spark,alunarbeach/spark,kissmetrics/spark,dongjoon-hyun/spark,highfei2011/spark,sureshthalamati/spark,wangmiao1981/spark,mkolod/incubator-spark,rikima/spark,lvdongr/spark,ConeyLiu/spark,nchammas/spark,aray/spark,hvanhovell/spark,bravo-zhang/spark,techaddict/spark