test: Add playlist testcases for nonexisting playlists
test: Add playlist testcases for nonexisting playlists

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