*: Add some unit tests
*: Add some unit tests

8cbx/tidb,yangwenmai/tidb,pingcap/tidb,JinheLin/tidb,ngaut/tidb,qhsong/tidb,zimulala/tidb,astaxie/tidb,ming-relax/tidb,gaocegege/tidb,simon-xia/tidb,ngaut/tidb,cosmtrek/tidb,gaocegege/tidb,EvilMcJerkface/tidb,wusphinx/tidb,zs634134578/tidb,cosmtrek/tidb,yuanwhy/tidb,spongedu/tidb,silenceper/tidb,ngaut/tidb,louishust/tidb,EvilMcJerkface/tidb,silenceper/tidb,Cofyc/tidb,pingcap/tidb,liyu4/tidb,qhsong/tidb,kyle-wang/tidb,pingcap/tidb,ueizhou/tidb,XuHuaiyu/tidb,ueizhou/tidb,Nify/tidb,qiuyesuifeng/tidb,yuanwhy/tidb,andelf/tidb,pingcap/tidb,Nify/tidb,c4pt0r/tidb,astaxie/tidb,silentred/tidb,zs634134578/tidb,XuHuaiyu/tidb,silentred/tidb,Cofyc/tidb,kyle-wang/tidb,myrice/tidb,CodeRushing/tidb,ming-relax/tidb,ngaut/tidb,mccxj/tidb,wusphinx/tidb,kyle-wang/tidb,c4pt0r/tidb,coocood/tidb,JinheLin/tidb,yangwenmai/tidb,qiuyesuifeng/tidb,andelf/tidb,louishust/tidb,spongedu/tidb,liyu4/tidb,8cbx/tidb,ngaut/tidb,kyle-wang/tidb,ngaut/tidb,c4pt0r/tidb,kyle-wang/tidb,tiancaiamao/tidb,zimulala/tidb,coocood/tidb,CodeRushing/tidb,pingcap/tidb,c4pt0r/tidb,c4pt0r/tidb,anywhy/tidb,tiancaiamao/tidb,myrice/tidb,mccxj/tidb,simon-xia/tidb,pingcap/tidb,anywhy/tidb,c4pt0r/tidb,kyle-wang/tidb