{
	package Maths;
	sub factorial {
		my $n = int(shift);
		die "does not compute" if $n<0;
		return $n if $n<2;
		$n * factorial($n - 1);
	}
}

use Test::More;
use Test::Exception;

my @results = qw/ 0 1 2 6 24 120 720 /;
for (0 .. $#results)
{
	lives_and { is Maths::factorial($_), $results[$_] } "Factorial of $_";
}

dies_ok { Maths::factorial(-2) } "Factorial of negative number";

done_testing;