Update assertion with correct error name
Update assertion with correct error name

jackwilsdon/beets,SusannaMaria/beets,ibmibmibm/beets,SusannaMaria/beets,ibmibmibm/beets,beetbox/beets,beetbox/beets,SusannaMaria/beets,ibmibmibm/beets,shamangeorge/beets,shamangeorge/beets,ibmibmibm/beets,SusannaMaria/beets,pkess/beets,pkess/beets,sampsyo/beets,jackwilsdon/beets,jackwilsdon/beets,beetbox/beets,sampsyo/beets,jackwilsdon/beets,beetbox/beets,sampsyo/beets,shamangeorge/beets,sampsyo/beets,shamangeorge/beets,pkess/beets,pkess/beets