added tests for data when cache directory is missing
added tests for data when cache directory is missing

AustereCuriosity/astropy,pllim/astropy,aleksandr-bakanov/astropy,MSeifert04/astropy,saimn/astropy,dhomeier/astropy,lpsinger/astropy,larrybradley/astropy,saimn/astropy,stargaser/astropy,larrybradley/astropy,aleksandr-bakanov/astropy,pllim/astropy,aleksandr-bakanov/astropy,pllim/astropy,AustereCuriosity/astropy,kelle/astropy,joergdietrich/astropy,DougBurke/astropy,funbaker/astropy,dhomeier/astropy,larrybradley/astropy,bsipocz/astropy,tbabej/astropy,tbabej/astropy,StuartLittlefair/astropy,dhomeier/astropy,joergdietrich/astropy,StuartLittlefair/astropy,dhomeier/astropy,AustereCuriosity/astropy,dhomeier/astropy,astropy/astropy,mhvk/astropy,joergdietrich/astropy,funbaker/astropy,joergdietrich/astropy,kelle/astropy,astropy/astropy,larrybradley/astropy,lpsinger/astropy,AustereCuriosity/astropy,pllim/astropy,DougBurke/astropy,saimn/astropy,pllim/astropy,lpsinger/astropy,MSeifert04/astropy,lpsinger/astropy,kelle/astropy,MSeifert04/astropy,AustereCuriosity/astropy,astropy/astropy,MSeifert04/astropy,lpsinger/astropy,bsipocz/astropy,mhvk/astropy,funbaker/astropy,kelle/astropy,mhvk/astropy,StuartLittlefair/astropy,saimn/astropy,astropy/astropy,funbaker/astropy,StuartLittlefair/astropy,kelle/astropy,larrybradley/astropy,stargaser/astropy,astropy/astropy,stargaser/astropy,bsipocz/astropy,mhvk/astropy,stargaser/astropy,tbabej/astropy,aleksandr-bakanov/astropy,bsipocz/astropy,saimn/astropy,DougBurke/astropy,DougBurke/astropy,tbabej/astropy,joergdietrich/astropy,StuartLittlefair/astropy,mhvk/astropy,tbabej/astropy