use strict;
use warnings;

use Math::Combinatorics qw( permute );
use Test::More;

my @match_wanted = qw( abc bca cab cba bac acb );
my @match_unwanted = qw( aab abbc acc );
my @charset = qw( a b c );

my %valid = map { join( '', @$_ ) => 1 } permute( @charset );

sub match
{
    my $s = shift;
    return( exists $valid{$s} ? 1 : 0 );
}

plan 'tests' => ( scalar @match_wanted + scalar @match_unwanted );

ok(   match( $_ ), "matches '$_'" )        for @match_wanted;
ok( ! match( $_ ), "does not match '$_'" ) for @match_unwanted;