What are good alternatives to test discovery (prove), and how do they compare?

# Example of using Test::More in Perl

use Test::More;

# Test a basic function
sub add {
    my ($a, $b) = @_;
    return $a + $b;
}

# Begin testing
ok(add(1, 2) == 3, 'Adding 1 and 2 should return 3');
ok(add(-1, 1) == 0, 'Adding -1 and 1 should return 0');

done_testing();