Small update to 'Writing tests' section.
Small update to 'Writing tests' section.

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