Add unit test
Add unit test

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