Add tests of YAML serialization
Add tests of YAML serialization

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