I wrote this script to play the above purity test:

#!/usr/bin/perl -w

use strict;
use Term::ReadKey;

my %answer;
while(<DATA>) {
    if (/^\.\.\./) {
        chomp;
        print "$_ (y/n)";
        my $ans = '';
        ReadMode('cbreak');
        $ans = ReadKey(0) while ($ans ne 'y' and $ans ne 'n');
        print "$ans\n";
        ReadMode('normal');
        $answer{$ans}++;
        $answer{t}++;
    } else {
        print;
    }
}

my $py = $answer{y} / $answer{t} * 100;
my $pn = $answer{n} / $answer{t} * 100;

print <<"EOF";
Results:

You answered:

    $answer{y} 'yes' ($py %)
    $answer{n} 'no' ($pn %)
EOF

__DATA__
[download]

(Copy and paste the purity test after __DATA__)