Add test for negative indexes in `at` method
Add test for negative indexes in `at` method
oss-practice/backbone,vin100bk/backbone,cgvarela/backbone,leimd/backbone,liudianpeng/backbone,Connectlegendary/backbone,linalu1/backbone,closeio/backbone,chyeh727/backbone,closeio/backbone,zgl2007dj/backbone,moimikey/backbone,gmaclennan/backbone,darrrk/backbone,zgl2007dj/backbone,sumyfly/backbone,huanglp47/backbone,webcoding/backbone,moccen/backbone,au-phiware/backbone,lastjune/backbone,sueyeh/backbone,moimikey/backbone,timebackzhou/backbone,ohbarye/backbone,aihua/backbone,sunday-star/backbone,Sachin-Ganesh/backbone,zhangwei001/backbone,ridixcr/backbone,webcoding/backbone,megawac/backbone,chyeh727/backbone,yuhualingfeng/backbone,Bug2014/backbone,wangdahoo/backbone,Connectlegendary/backbone,jewsroch/backbone,craigmichaelmartin/backbone,getshuvo/backbone,trizko/backbone,premkumargithub/backbone,Krasnyanskiy/backbone,zhangwei001/backbone,premkumargithub/backbone,kuychaco/backbone,Flip120/backbone,tadwhitaker/backbone,amitpatange88/backbonejs,jashkenas/backbone,elma-cao/backbone,paulfalgout/backbone,zhoufan879/backbone,sitexa/backbone,jungjung917/backbone,wangcan2014/backbone,nikolas/backbone,jashkenas/backbone,wjb12/backbone,pandoraui/backbone,streamablevideo/backbone,mrblueblue/backbone,amitpatange88/backbonejs,feychenie/backbone,DannyDelott/backbone,Niades/backbone,DannyDelott/backbone,wxmfront/backbone,ntgn81/backbone,alekskorolev/lightbones,cgvarela/backbone,ThiagoGarciaAlves/backbone,ywenjinlin/backbone,wangdahoo/backbone,ridixcr/backbone,jungjung917/backbone,zdespolit/backbone,anhtholee/backbone,Diwahars/backbone,ereddate/backbone,nvoron23/backbone,ereddate/backbone,wushuyi/backbone,elma-cao/backbone,alekskorolev/lightbones,heroazure/backbone,ywenjinlin/backbone,guigrpa/backbone,platinumazure/backbone,udhayam/backbone,howtolearntocode/backbone,zdespolit/backbone,braddunbar/backbone,ohbarye/backbone,au-phiware/backbone,Sachin-Ganesh/backbone,GrimDerp/backbone,feychenie/backbone,lujocom/backbone,udhayam/backbone,akre54/backbone,heroazure/backbone,lujocom/backbone,elancom/backbone,gougouGet/backbone,tzkKrbys/backbone,sumyfly/backbone,darrrk/backbone,linalu1/backbone,huanglp47/backbone,kuychaco/backbone,GrimDerp/backbone,zhoufan879/backbone,getshuvo/backbone,7213/backbone,leimd/backbone,dcheepurupalli/backbone,embarknow/backbone,vincent1988/backbone,guahanweb/backbone,jmeas/backbone,FishbaitHarry/backbone,mrblueblue/backbone,neocotic/hipbone,pandoraui/backbone,FishbaitHarry/backbone,Diwahars/backbone,yawenl/backbone,moccen/backbone,ThiagoGarciaAlves/backbone,jridgewell/backbone,yawenl/backbone,paulfalgout/backbone,dcheepurupalli/backbone,nvoron23/backbone,tibic/backbone,Flip120/backbone,youprofit/backbone,gougouGet/backbone,jewsroch/backbone,wangcan2014/backbone,ppker/backbone,sitexa/backbone,liudianpeng/backbone,guahanweb/backbone,wjb12/backbone,JesseQin/backbone,IsoldaJS/isolda-models,cailong1028/backbone,akre54/backbone,yuhualingfeng/backbone,howtolearntocode/backbone,tadwhitaker/backbone,Krasnyanskiy/backbone,zhangdimelody/backbone,tzkKrbys/backbone,aihua/backbone,rashmisajjan/backbone,fanhc019/backbone,jmeas/backbone,nikolas/backbone,wxmfront/backbone,elancom/backbone,Bug2014/backbone,ntgn81/backbone,JesseQin/backbone,Niades/backbone,IsoldaJS/isolda-pubsub,braddunbar/backbone,anhtholee/backbone,craigmichaelmartin/backbone,rashmisajjan/backbone,platinumazure/backbone,gdi2290/backbone,cailong1028/backbone,streamablevideo/backbone,jridgewell/backbone,embarknow/backbone,dak/backbone,neocotic/hipbone,gmaclennan/backbone,7213/backbone,dak/backbone,zhangdimelody/backbone,sueyeh/backbone,trizko/backbone,sunday-star/backbone,lastjune/backbone,tibic/backbone,youprofit/backbone,vin100bk/backbone,fanhc019/backbone,wushuyi/backbone,timebackzhou/backbone,vincent1988/backbone,ppker/backbone