#NEWLINE# def test_add_artist_updates_artist_list( ) : #NEWLINE# #INDENT# mgrs = [ LayerArtist ( Data ( label = 'A' ) , None ) ] #NEWLINE# model = LayerArtistModel ( mgrs ) #NEWLINE# model . add_artist ( 0 , LayerArtist ( Data ( label = 'B' ) , None ) ) #NEWLINE# assert ( len ( mgrs ) == 2 )