use strict;
use warnings;
use Test::More;

use Scalar::Util qw(weaken isweak);
use Devel::Refcount qw(refcount);

my $A = bless {}, 'Monkey';
is(refcount($A), 1, 'an object has a refcount');

my $B = $A;
is(refcount($A), 2, 'additional ref to the object increases the refcount');

$B = undef;
is(refcount($A), 1, 'removing a ref to the object decreases the refcount');

do {
	my $C = $A;
	is(refcount($A), 2, 'reference in a scope increases refcount');
};

is(refcount($A), 1, '$C fell out of scope, so decreased ref count');

my $D = $A;
is(refcount($A), 2, 'another ref which will increase ref count');

weaken $D;
is(refcount($A), 1, 'weakening the ref means it is not included in the ref count');
ok($A == $D, 'yet $A and $D are still the same object');

my $destroyed = 0;
sub Monkey::DESTROY { $destroyed++ };

$A = undef;
is($destroyed, 1, 'undefining $A destroyed the object; $D was a weak ref so did not prevent destruction');

ok(!defined $D, '$D is now undefined');

done_testing;