TST: skip knuth test when scipy not installed
TST: skip knuth test when scipy not installed

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