Adding tests for credentials plugin.
Adding tests for credentials plugin.

wangyikai/grpc,deepaklukose/grpc,perumaalgoog/grpc,pszemus/grpc,podsvirov/grpc,wcevans/grpc,bogdandrutu/grpc,msmania/grpc,rjshade/grpc,pszemus/grpc,greasypizza/grpc,podsvirov/grpc,firebase/grpc,kskalski/grpc,daniel-j-born/grpc,Vizerai/grpc,thunderboltsid/grpc,LuminateWireless/grpc,ncteisen/grpc,thunderboltsid/grpc,ncteisen/grpc,thinkerou/grpc,Crevil/grpc,baylabs/grpc,pmarks-net/grpc,kriswuollett/grpc,pszemus/grpc,Vizerai/grpc,LuminateWireless/grpc,dgquintas/grpc,thinkerou/grpc,kpayson64/grpc,pszemus/grpc,stanley-cheung/grpc,yongni/grpc,miselin/grpc,murgatroid99/grpc,vjpai/grpc,Vizerai/grpc,wangyikai/grpc,jboeuf/grpc,VcamX/grpc,makdharma/grpc,donnadionne/grpc,miselin/grpc,fuchsia-mirror/third_party-grpc,a-veitch/grpc,zhimingxie/grpc,donnadionne/grpc,royalharsh/grpc,jtattermusch/grpc,msmania/grpc,matt-kwong/grpc,yongni/grpc,vsco/grpc,Vizerai/grpc,bjori/grpc,perumaalgoog/grpc,fuchsia-mirror/third_party-grpc,maxwell-demon/grpc,a11r/grpc,donnadionne/grpc,ananthonline/grpc,rjshade/grpc,PeterFaiman/ruby-grpc-minimal,zhimingxie/grpc,carl-mastrangelo/grpc,sreecha/grpc,podsvirov/grpc,nicolasnoble/grpc,stanley-cheung/grpc,grpc/grpc,adelez/grpc,thinkerou/grpc,muxi/grpc,msiedlarek/grpc,hstefan/grpc,leifurhauks/grpc,maxwell-demon/grpc,infinit/grpc,nicolasnoble/grpc,royalharsh/grpc,kpayson64/grpc,tengyifei/grpc,daniel-j-born/grpc,bogdandrutu/grpc,yugui/grpc,yang-g/grpc,apolcyn/grpc,leifurhauks/grpc,nicolasnoble/grpc,kskalski/grpc,stanley-cheung/grpc,murgatroid99/grpc,vjpai/grpc,makdharma/grpc,PeterFaiman/ruby-grpc-minimal,msiedlarek/grpc,vsco/grpc,simonkuang/grpc,vjpai/grpc,yongni/grpc,tamihiro/grpc,vsco/grpc,fuchsia-mirror/third_party-grpc,dgquintas/grpc,wangyikai/grpc,ctiller/grpc,VcamX/grpc,muxi/grpc,deepaklukose/grpc,philcleveland/grpc,madongfly/grpc,MakMukhi/grpc,donnadionne/grpc,grani/grpc,thunderboltsid/grpc,matt-kwong/grpc,ctiller/grpc,vsco/grpc,ppietrasa/grpc,dklempner/grpc,quizlet/grpc,grani/grpc,arkmaxim/grpc,thunderboltsid/grpc,matt-kwong/grpc,dklempner/grpc,ctiller/grpc,dgquintas/grpc,vjpai/grpc,yugui/grpc,infinit/grpc,royalharsh/grpc,Vizerai/grpc,ofrobots/grpc,philcleveland/grpc,tamihiro/grpc,jboeuf/grpc,baylabs/grpc,PeterFaiman/ruby-grpc-minimal,kskalski/grpc,firebase/grpc,kskalski/grpc,adelez/grpc,zhimingxie/grpc,bogdandrutu/grpc,sreecha/grpc,arkmaxim/grpc,thinkerou/grpc,ejona86/grpc,infinit/grpc,kpayson64/grpc,muxi/grpc,royalharsh/grpc,grpc/grpc,bogdandrutu/grpc,geffzhang/grpc,chrisdunelm/grpc,soltanmm-google/grpc,zhimingxie/grpc,andrewpollock/grpc,arkmaxim/grpc,royalharsh/grpc,rjshade/grpc,stanley-cheung/grpc,yang-g/grpc,vsco/grpc,ananthonline/grpc,grpc/grpc,andrewpollock/grpc,VcamX/grpc,ppietrasa/grpc,pszemus/grpc,w4-sjcho/grpc,daniel-j-born/grpc,soltanmm-google/grpc,miselin/grpc,muxi/grpc,Crevil/grpc,kumaralokgithub/grpc,jcanizales/grpc,firebase/grpc,kpayson64/grpc,daniel-j-born/grpc,yang-g/grpc,chrisdunelm/grpc,goldenbull/grpc,pmarks-net/grpc,yongni/grpc,dgquintas/grpc,MakMukhi/grpc,mehrdada/grpc,rjshade/grpc,stanley-cheung/grpc,jboeuf/grpc,donnadionne/grpc,baylabs/grpc,simonkuang/grpc,adelez/grpc,7anner/grpc,bjori/grpc,jtattermusch/grpc,kriswuollett/grpc,infinit/grpc,carl-mastrangelo/grpc,leifurhauks/grpc,vsco/grpc,w4-sjcho/grpc,chrisdunelm/grpc,murgatroid99/grpc,rjshade/grpc,tengyifei/grpc,thunderboltsid/grpc,ejona86/grpc,apolcyn/grpc,kpayson64/grpc,greasypizza/grpc,arkmaxim/grpc,kumaralokgithub/grpc,hstefan/grpc,thinkerou/grpc,firebase/grpc,muxi/grpc,y-zeng/grpc,murgatroid99/grpc,ejona86/grpc,pszemus/grpc,y-zeng/grpc,fuchsia-mirror/third_party-grpc,kumaralokgithub/grpc,donnadionne/grpc,fuchsia-mirror/third_party-grpc,jboeuf/grpc,greasypizza/grpc,soltanmm/grpc,donnadionne/grpc,baylabs/grpc,grani/grpc,Crevil/grpc,pszemus/grpc,kskalski/grpc,kriswuollett/grpc,mehrdada/grpc,leifurhauks/grpc,greasypizza/grpc,goldenbull/grpc,a11r/grpc,nicolasnoble/grpc,chrisdunelm/grpc,makdharma/grpc,baylabs/grpc,stanley-cheung/grpc,philcleveland/grpc,PeterFaiman/ruby-grpc-minimal,maxwell-demon/grpc,firebase/grpc,muxi/grpc,msiedlarek/grpc,grpc/grpc,dklempner/grpc,ipylypiv/grpc,ananthonline/grpc,carl-mastrangelo/grpc,makdharma/grpc,y-zeng/grpc,goldenbull/grpc,arkmaxim/grpc,rjshade/grpc,thinkerou/grpc,muxi/grpc,pszemus/grpc,miselin/grpc,7anner/grpc,Crevil/grpc,malexzx/grpc,grani/grpc,LuminateWireless/grpc,ejona86/grpc,yugui/grpc,muxi/grpc,bjori/grpc,andrewpollock/grpc,dklempner/grpc,chrisdunelm/grpc,dgquintas/grpc,maxwell-demon/grpc,kpayson64/grpc,stanley-cheung/grpc,leifurhauks/grpc,soltanmm-google/grpc,kpayson64/grpc,y-zeng/grpc,Crevil/grpc,sreecha/grpc,thinkerou/grpc,grpc/grpc,infinit/grpc,ctiller/grpc,MakMukhi/grpc,ppietrasa/grpc,mehrdada/grpc,kumaralokgithub/grpc,podsvirov/grpc,quizlet/grpc,donnadionne/grpc,msmania/grpc,pszemus/grpc,bjori/grpc,sreecha/grpc,ncteisen/grpc,grpc/grpc,geffzhang/grpc,tamihiro/grpc,andrewpollock/grpc,ejona86/grpc,Vizerai/grpc,daniel-j-born/grpc,perumaalgoog/grpc,msiedlarek/grpc,a-veitch/grpc,rjshade/grpc,pmarks-net/grpc,kumaralokgithub/grpc,thunderboltsid/grpc,mehrdada/grpc,ejona86/grpc,fuchsia-mirror/third_party-grpc,jcanizales/grpc,adelez/grpc,philcleveland/grpc,miselin/grpc,goldenbull/grpc,tamihiro/grpc,ejona86/grpc,mehrdada/grpc,perumaalgoog/grpc,mehrdada/grpc,greasypizza/grpc,podsvirov/grpc,ipylypiv/grpc,VcamX/grpc,muxi/grpc,philcleveland/grpc,murgatroid99/grpc,tamihiro/grpc,w4-sjcho/grpc,thunderboltsid/grpc,malexzx/grpc,w4-sjcho/grpc,VcamX/grpc,stanley-cheung/grpc,firebase/grpc,msiedlarek/grpc,goldenbull/grpc,geffzhang/grpc,apolcyn/grpc,zhimingxie/grpc,dklempner/grpc,carl-mastrangelo/grpc,yang-g/grpc,murgatroid99/grpc,LuminateWireless/grpc,kriswuollett/grpc,ofrobots/grpc,wcevans/grpc,carl-mastrangelo/grpc,a-veitch/grpc,murgatroid99/grpc,makdharma/grpc,carl-mastrangelo/grpc,baylabs/grpc,ctiller/grpc,pmarks-net/grpc,zhimingxie/grpc,hstefan/grpc,pszemus/grpc,ncteisen/grpc,soltanmm/grpc,soltanmm/grpc,carl-mastrangelo/grpc,grpc/grpc,maxwell-demon/grpc,a-veitch/grpc,simonkuang/grpc,jtattermusch/grpc,nicolasnoble/grpc,pmarks-net/grpc,maxwell-demon/grpc,miselin/grpc,chrisdunelm/grpc,ipylypiv/grpc,daniel-j-born/grpc,chrisdunelm/grpc,thinkerou/grpc,hstefan/grpc,carl-mastrangelo/grpc,jcanizales/grpc,ctiller/grpc,tengyifei/grpc,arkmaxim/grpc,infinit/grpc,goldenbull/grpc,tengyifei/grpc,tengyifei/grpc,geffzhang/grpc,maxwell-demon/grpc,jboeuf/grpc,soltanmm/grpc,soltanmm-google/grpc,w4-sjcho/grpc,soltanmm/grpc,apolcyn/grpc,nicolasnoble/grpc,grani/grpc,ipylypiv/grpc,jcanizales/grpc,adelez/grpc,yang-g/grpc,grpc/grpc,vjpai/grpc,miselin/grpc,makdharma/grpc,hstefan/grpc,pszemus/grpc,nicolasnoble/grpc,yang-g/grpc,muxi/grpc,wangyikai/grpc,ejona86/grpc,thunderboltsid/grpc,a-veitch/grpc,fuchsia-mirror/third_party-grpc,a11r/grpc,kriswuollett/grpc,tamihiro/grpc,MakMukhi/grpc,dgquintas/grpc,a11r/grpc,baylabs/grpc,ejona86/grpc,miselin/grpc,soltanmm-google/grpc,malexzx/grpc,jtattermusch/grpc,msmania/grpc,ipylypiv/grpc,dgquintas/grpc,kumaralokgithub/grpc,mehrdada/grpc,kskalski/grpc,ctiller/grpc,w4-sjcho/grpc,leifurhauks/grpc,wangyikai/grpc,kpayson64/grpc,a11r/grpc,greasypizza/grpc,daniel-j-born/grpc,donnadionne/grpc,quizlet/grpc,simonkuang/grpc,grpc/grpc,jtattermusch/grpc,ofrobots/grpc,ctiller/grpc,andrewpollock/grpc,ejona86/grpc,w4-sjcho/grpc,muxi/grpc,perumaalgoog/grpc,firebase/grpc,madongfly/grpc,chrisdunelm/grpc,simonkuang/grpc,jtattermusch/grpc,hstefan/grpc,y-zeng/grpc,bogdandrutu/grpc,VcamX/grpc,royalharsh/grpc,adelez/grpc,ppietrasa/grpc,jtattermusch/grpc,philcleveland/grpc,andrewpollock/grpc,MakMukhi/grpc,podsvirov/grpc,thinkerou/grpc,philcleveland/grpc,miselin/grpc,jcanizales/grpc,jcanizales/grpc,sreecha/grpc,y-zeng/grpc,ofrobots/grpc,podsvirov/grpc,deepaklukose/grpc,leifurhauks/grpc,kskalski/grpc,mehrdada/grpc,grani/grpc,royalharsh/grpc,ppietrasa/grpc,greasypizza/grpc,quizlet/grpc,dgquintas/grpc,dklempner/grpc,stanley-cheung/grpc,mehrdada/grpc,PeterFaiman/ruby-grpc-minimal,jboeuf/grpc,firebase/grpc,grpc/grpc,quizlet/grpc,ncteisen/grpc,7anner/grpc,apolcyn/grpc,kpayson64/grpc,andrewpollock/grpc,PeterFaiman/ruby-grpc-minimal,ofrobots/grpc,fuchsia-mirror/third_party-grpc,matt-kwong/grpc,andrewpollock/grpc,vjpai/grpc,Crevil/grpc,Vizerai/grpc,adelez/grpc,ncteisen/grpc,yugui/grpc,dklempner/grpc,yugui/grpc,ctiller/grpc,murgatroid99/grpc,w4-sjcho/grpc,thinkerou/grpc,ncteisen/grpc,apolcyn/grpc,ctiller/grpc,y-zeng/grpc,makdharma/grpc,sreecha/grpc,murgatroid99/grpc,vsco/grpc,7anner/grpc,quizlet/grpc,wcevans/grpc,ananthonline/grpc,jboeuf/grpc,apolcyn/grpc,kriswuollett/grpc,malexzx/grpc,msiedlarek/grpc,LuminateWireless/grpc,kumaralokgithub/grpc,sreecha/grpc,soltanmm-google/grpc,a-veitch/grpc,chrisdunelm/grpc,simonkuang/grpc,pmarks-net/grpc,baylabs/grpc,ofrobots/grpc,LuminateWireless/grpc,philcleveland/grpc,dklempner/grpc,pmarks-net/grpc,ncteisen/grpc,wangyikai/grpc,a-veitch/grpc,yongni/grpc,ipylypiv/grpc,jcanizales/grpc,tengyifei/grpc,chrisdunelm/grpc,7anner/grpc,bogdandrutu/grpc,infinit/grpc,ppietrasa/grpc,bogdandrutu/grpc,wcevans/grpc,Crevil/grpc,soltanmm/grpc,ncteisen/grpc,royalharsh/grpc,maxwell-demon/grpc,LuminateWireless/grpc,ofrobots/grpc,fuchsia-mirror/third_party-grpc,podsvirov/grpc,andrewpollock/grpc,madongfly/grpc,carl-mastrangelo/grpc,wcevans/grpc,stanley-cheung/grpc,simonkuang/grpc,fuchsia-mirror/third_party-grpc,ananthonline/grpc,grani/grpc,y-zeng/grpc,jtattermusch/grpc,ppietrasa/grpc,podsvirov/grpc,perumaalgoog/grpc,mehrdada/grpc,PeterFaiman/ruby-grpc-minimal,grpc/grpc,tengyifei/grpc,ncteisen/grpc,sreecha/grpc,madongfly/grpc,kriswuollett/grpc,kriswuollett/grpc,7anner/grpc,rjshade/grpc,tengyifei/grpc,matt-kwong/grpc,dgquintas/grpc,MakMukhi/grpc,VcamX/grpc,msiedlarek/grpc,sreecha/grpc,a11r/grpc,madongfly/grpc,murgatroid99/grpc,a-veitch/grpc,msiedlarek/grpc,donnadionne/grpc,thinkerou/grpc,nicolasnoble/grpc,zhimingxie/grpc,deepaklukose/grpc,quizlet/grpc,wangyikai/grpc,greasypizza/grpc,matt-kwong/grpc,geffzhang/grpc,firebase/grpc,Vizerai/grpc,soltanmm-google/grpc,jtattermusch/grpc,ctiller/grpc,zhimingxie/grpc,sreecha/grpc,kpayson64/grpc,vjpai/grpc,jtattermusch/grpc,arkmaxim/grpc,hstefan/grpc,malexzx/grpc,deepaklukose/grpc,msmania/grpc,madongfly/grpc,grpc/grpc,vsco/grpc,wcevans/grpc,chrisdunelm/grpc,carl-mastrangelo/grpc,kskalski/grpc,infinit/grpc,stanley-cheung/grpc,philcleveland/grpc,vjpai/grpc,wcevans/grpc,yugui/grpc,jtattermusch/grpc,yugui/grpc,wangyikai/grpc,dgquintas/grpc,deepaklukose/grpc,leifurhauks/grpc,bogdandrutu/grpc,dklempner/grpc,ananthonline/grpc,wangyikai/grpc,jcanizales/grpc,y-zeng/grpc,adelez/grpc,Crevil/grpc,perumaalgoog/grpc,ctiller/grpc,thinkerou/grpc,ncteisen/grpc,a-veitch/grpc,yugui/grpc,7anner/grpc,leifurhauks/grpc,tamihiro/grpc,vjpai/grpc,yongni/grpc,soltanmm/grpc,jtattermusch/grpc,deepaklukose/grpc,malexzx/grpc,ananthonline/grpc,VcamX/grpc,PeterFaiman/ruby-grpc-minimal,madongfly/grpc,MakMukhi/grpc,wcevans/grpc,matt-kwong/grpc,Vizerai/grpc,stanley-cheung/grpc,goldenbull/grpc,makdharma/grpc,goldenbull/grpc,vjpai/grpc,MakMukhi/grpc,geffzhang/grpc,carl-mastrangelo/grpc,vjpai/grpc,ananthonline/grpc,PeterFaiman/ruby-grpc-minimal,quizlet/grpc,daniel-j-born/grpc,ipylypiv/grpc,dgquintas/grpc,bjori/grpc,ipylypiv/grpc,jboeuf/grpc,deepaklukose/grpc,kumaralokgithub/grpc,donnadionne/grpc,quizlet/grpc,yang-g/grpc,nicolasnoble/grpc,nicolasnoble/grpc,yongni/grpc,yang-g/grpc,Vizerai/grpc,rjshade/grpc,w4-sjcho/grpc,msmania/grpc,ipylypiv/grpc,zhimingxie/grpc,soltanmm/grpc,perumaalgoog/grpc,daniel-j-born/grpc,bogdandrutu/grpc,royalharsh/grpc,goldenbull/grpc,ofrobots/grpc,yongni/grpc,ofrobots/grpc,greasypizza/grpc,matt-kwong/grpc,soltanmm-google/grpc,LuminateWireless/grpc,deepaklukose/grpc,matt-kwong/grpc,grani/grpc,malexzx/grpc,nicolasnoble/grpc,VcamX/grpc,vsco/grpc,maxwell-demon/grpc,msmania/grpc,tamihiro/grpc,tengyifei/grpc,kumaralokgithub/grpc,yongni/grpc,pmarks-net/grpc,malexzx/grpc,soltanmm/grpc,LuminateWireless/grpc,yugui/grpc,carl-mastrangelo/grpc,ejona86/grpc,jboeuf/grpc,ppietrasa/grpc,kskalski/grpc,jboeuf/grpc,thunderboltsid/grpc,7anner/grpc,baylabs/grpc,MakMukhi/grpc,sreecha/grpc,mehrdada/grpc,a11r/grpc,pmarks-net/grpc,nicolasnoble/grpc,simonkuang/grpc,msmania/grpc,firebase/grpc,infinit/grpc,vjpai/grpc,bjori/grpc,soltanmm-google/grpc,simonkuang/grpc,Crevil/grpc,ppietrasa/grpc,bjori/grpc,kpayson64/grpc,arkmaxim/grpc,PeterFaiman/ruby-grpc-minimal,firebase/grpc,mehrdada/grpc,geffzhang/grpc,hstefan/grpc,wcevans/grpc,apolcyn/grpc,jcanizales/grpc,makdharma/grpc,bjori/grpc,jboeuf/grpc,sreecha/grpc,firebase/grpc,muxi/grpc,kriswuollett/grpc,msiedlarek/grpc,a11r/grpc,adelez/grpc,grani/grpc,ananthonline/grpc,madongfly/grpc,bjori/grpc,apolcyn/grpc,7anner/grpc,tamihiro/grpc,geffzhang/grpc,perumaalgoog/grpc,pszemus/grpc,malexzx/grpc,ejona86/grpc,geffzhang/grpc,madongfly/grpc,yang-g/grpc,a11r/grpc,msmania/grpc,donnadionne/grpc,arkmaxim/grpc,jboeuf/grpc,hstefan/grpc,Vizerai/grpc,ncteisen/grpc