add more assert statements to tests
add more assert statements to tests

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