Add unit tests for the show command
Add unit tests for the show command

Add unit tests for the methods of the ShowCommands class that it has
been committed without tests.

Change-Id: I94e3f4bc8c166a612c653065c6f032eb5d71a231

vefimova/rally,vganapath/rally,gluke77/rally,cernops/rally,varunarya10/rally,gluke77/rally,amit0701/rally,openstack/rally,aforalee/RRally,group-policy/rally,afaheem88/rally,gluke77/rally,group-policy/rally,pandeyop/rally,varunarya10/rally,vponomaryov/rally,ytsarev/rally,pyKun/rally,cernops/rally,amit0701/rally,vganapath/rally,eonpatapon/rally,yeming233/rally,aforalee/RRally,pyKun/rally,paboldin/rally,yeming233/rally,eonpatapon/rally,openstack/rally,aplanas/rally,paboldin/rally,vefimova/rally,eayunstack/rally,group-policy/rally,paboldin/rally,pandeyop/rally,redhat-openstack/rally,afaheem88/rally,openstack/rally,vganapath/rally,gluke77/rally,amit0701/rally,redhat-openstack/rally,aplanas/rally,eayunstack/rally,go-bears/rally,openstack/rally,vganapath/rally,shdowofdeath/rally,vponomaryov/rally,ytsarev/rally,eayunstack/rally,go-bears/rally,shdowofdeath/rally