extended test_fields_func to check output
extended test_fields_func to check output

xsteadfastx/beets,Freso/beets,m-urban/beets,pkess/beets,sampsyo/beets,kareemallen/beets,Freso/beets,sampsyo/beets,shamangeorge/beets,SusannaMaria/beets,beetbox/beets,jackwilsdon/beets,jcoady9/beets,mried/beets,mried/beets,kareemallen/beets,lengtche/beets,pkess/beets,madmouser1/beets,m-urban/beets,beetbox/beets,ibmibmibm/beets,mosesfistos1/beetbox,jackwilsdon/beets,shamangeorge/beets,jmwatte/beets,marcuskrahl/beets,beetbox/beets,MyTunesFreeMusic/privacy-policy,Freso/beets,diego-plan9/beets,MyTunesFreeMusic/privacy-policy,kareemallen/beets,mosesfistos1/beetbox,asteven/beets,SusannaMaria/beets,artemutin/beets,jmwatte/beets,marcuskrahl/beets,ibmibmibm/beets,mried/beets,tima/beets,madmouser1/beets,ibmibmibm/beets,LordSputnik/beets,jcoady9/beets,swt30/beets,lengtche/beets,Freso/beets,parapente/beets,jackwilsdon/beets,MyTunesFreeMusic/privacy-policy,tima/beets,diego-plan9/beets,xsteadfastx/beets,marcuskrahl/beets,shamangeorge/beets,marcuskrahl/beets,artemutin/beets,artemutin/beets,swt30/beets,LordSputnik/beets,tima/beets,MyTunesFreeMusic/privacy-policy,jmwatte/beets,jcoady9/beets,parapente/beets,Kraymer/beets,tima/beets,jmwatte/beets,lengtche/beets,jackwilsdon/beets,swt30/beets,SusannaMaria/beets,LordSputnik/beets,SusannaMaria/beets,parapente/beets,asteven/beets,lengtche/beets,parapente/beets,madmouser1/beets,pkess/beets,swt30/beets,sampsyo/beets,jcoady9/beets,kelvinhammond/beets,mried/beets,m-urban/beets,LordSputnik/beets,mosesfistos1/beetbox,artemutin/beets,beetbox/beets,diego-plan9/beets,Kraymer/beets,madmouser1/beets,kelvinhammond/beets,kelvinhammond/beets,m-urban/beets,Kraymer/beets,xsteadfastx/beets,xsteadfastx/beets,kareemallen/beets,asteven/beets,kelvinhammond/beets,diego-plan9/beets,shamangeorge/beets,pkess/beets,asteven/beets,Kraymer/beets,mosesfistos1/beetbox,ibmibmibm/beets,sampsyo/beets