For measuring strength, I used entropy. For example,

#!/usr/bin/perl -l

use strict;
use warnings;
use Data::Password::Entropy;
use Data::Password::Manager
    qw(pw_gen
       pw_valid
       pw_obscure
       pw_clean
       pw_get);

my $cleartext = 'Khen1950fx';
my $pass = pw_gen($cleartext);
my $ok = pw_valid($cleartext, $pass); 
print "Valid" if $ok eq 1;
print "Entropy is ", password_entropy($pass), " bits.";
my $clean_text = pw_clean($ok);
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