Test suite: added ZUNION.
Test suite: added ZUNION.

WalterShe/predis,dominics/predis,protomouse/predis,RedisLabs/predis,CloudSide/predis,dzung2t/predis,mrkeng/predis,nguyenthaihan/predis,gencer/predis,johnhelmuth/predis,channelgrabber/predis,stokes3452/predis,oswaldderiemaecker/predis,lvbaosong/predis,zhangyancoder/predis,gopalindians/predis,SecureCloud-biz/predis,quangnguyen90/predis,RudyJessop/predis,nrk/predis,SwelenFrance/predis,vend/predis,moria/predis