Add a quick unit test for authentication.
Add a quick unit test for authentication.

larsbutler/gophercloud,sti-jans/gophercloud,jamiehannaford/gophercloud,jamiehannaford/gophercloud,pratikmallya/gophercloud,DSpeichert/gophercloud,jarosser06/gophercloud,rgbkrk/gophercloud,trumant/gophercloud,larsbutler/gophercloud,DSpeichert/gophercloud,jarosser06/gophercloud,sti-jans/gophercloud,dudymas/gophercloud,dudymas/gophercloud,clintonskitson/gophercloud,trumant/gophercloud,carolynvs/gophercloud,feiskyer/gophercloud,carolynvs/gophercloud,feiskyer/gophercloud,clintonskitson/gophercloud,rackspace/gophercloud,rgbkrk/gophercloud,timbyr/gophercloud,rackspace/gophercloud,timbyr/gophercloud,pratikmallya/gophercloud