use Bijection::XS qw/biject inverse bijection_set/;
my %unique;
for (0..5000) {
my $bi = biject($_);
$unique{$bi}++;
my $inv = inverse($bi);
is ($inv, $_, "reversable $_");
}
is (scalar keys %unique, 5001, 'all unique');
done_testing(5002);
1;