use Test::More qw(no_plan); eq_array([first_filter(qw/one two three/)], [qw/one two three/], "clean list doesn't get changed"); eq_array([first_filter(qw/one one one/)], [qw/one/], "simple repetition removed"); eq_array([first_filter(qw/one two one/)], [qw/one two/], "interleaved repetition removed");