added simple test for snr function
added simple test for snr function

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