use strict;
use warnings;

use Test::More tests => 3;

my $data     = {x => "Maria's"};
my $old      = \%$data;
my @allparms = sort keys %$data;
my @oldparms = @allparms;
my @expected = ("Maria''s");

my @result = map { (my $f = $data->{$_} || '') =~ s/'/''/g; $f } @allparms;

is_deeply \@result, \@expected, "apostrophe's are doubled";
is_deeply $data, $old, '$data is unchanged';
is_deeply \@allparms, \@oldparms, '@allparms is unchanged';