Actually do something useful with the engine_traits parameter, by appling a role...

[gitmo/MooseX-Storage.git] / t / 004_w_cycles.t

#!/usr/bin/perl

use strict;
use warnings;

use Test::More tests => 18;
use Test::Exception;

BEGIN {
    use_ok('MooseX::Storage');
}

=pod

This test demonstrates two things:

- cycles will not work in the default engine
- you can use a special metaclass to tell 
  MooseX::Storage to skip an attribute

=cut

{

    package Circular;
    use Moose;
    use MooseX::Storage;

    with Storage;

    has 'cycle' => (is => 'rw', isa => 'Circular');
}

{
    my $circular = Circular->new;
    isa_ok($circular, 'Circular');
    
    $circular->cycle($circular);
    
    throws_ok {
        $circular->pack;
    } qr/^Basic Engine does not support cycles/, 
    '... cannot collapse a cycle with the basic engine';
}

{
    my $packed_circular = { __CLASS__ => 'Circular' };
    $packed_circular->{cycle} = $packed_circular;

    throws_ok {
        Circular->unpack($packed_circular);
    } qr/^Basic Engine does not support cycles/, 
    '... cannot expand a cycle with the basic engine';
}

{

    package Tree;
    use Moose;
    use MooseX::Storage;

    with Storage;

    has 'node' => (is => 'rw');
    
    has 'children' => (
        is      => 'ro', 
        isa     => 'ArrayRef', 
        default => sub {[]}
    );
    
    has 'parent' => (
        metaclass => 'DoNotSerialize',
        is        => 'rw', 
        isa       => 'Tree',
    );
    
    sub add_child {
        my ($self, $child) = @_;
        $child->parent($self);
        push @{$self->children} => $child;
    }
}

{
    my $t = Tree->new(node => 100);
    isa_ok($t, 'Tree');
    
    is_deeply(
        $t->pack, 
        {
            __CLASS__ => 'Tree',
            node      => 100,
            children  => [],
        },
    '... got the right packed version');
    
    my $t2 = Tree->new(node => 200);
    isa_ok($t2, 'Tree');    
    
    $t->add_child($t2);
    
    is_deeply($t->children, [ $t2 ], '... got the right children in $t');
    
    is($t2->parent, $t, '... created the cycle correctly');
    isa_ok($t2->parent, 'Tree');        
    
    is_deeply(
        $t->pack, 
        {
            __CLASS__ => 'Tree',
            node      => 100,
            children  => [
               {
                   __CLASS__ => 'Tree',
                   node      => 200,
                   children  => [],            
               } 
            ],
        },
    '... got the right packed version (with parent attribute skipped in child)');    
    
    is_deeply(
        $t2->pack, 
        {
            __CLASS__ => 'Tree',
            node      => 200,
            children  => [],            
        },
    '... got the right packed version (with parent attribute skipped)');
}

### this fails with cycle detection on
{   package Double;
    use Moose;
    use MooseX::Storage;
    with Storage;
    
    has 'x' => ( is => 'rw', isa => 'HashRef' );
    has 'y' => ( is => 'rw', isa => 'HashRef' );
}

{   my $ref = {};

    my $double = Double->new( 'x' => $ref, 'y' => $ref );

    ### currently, the cycle checker's too naive to figure out this is not
    ### a problem, pass an empty hashref to the 2nd test to make sure it
    ### doesn't warn/die
    TODO: {
        local $TODO = "Cycle check is too naive";
        my $pack = eval { $double->pack; };
        ok( $pack,              "Object with 2 references packed" );
        ok( Double->unpack( $pack || {} ),
                                "   And unpacked again" );
    }
    
    my $pack = $double->pack( disable_cycle_check => 1 );
    ok( $pack,                  "   Object packs when cycle check is disabled");
    ok( Double->unpack( $pack ),
                                "   And unpacked again" );

}    

### the same as above, but now done with a trait
### this fails with cycle detection on
{   package DoubleNoCycle;
    use Moose;
    use MooseX::Storage;
    with Storage( traits => ['DisableCycleDetection'] );
    
    has 'x' => ( is => 'rw', isa => 'HashRef' );
    has 'y' => ( is => 'rw', isa => 'HashRef' );
}

{   my $ref = {};

    my $double = DoubleNoCycle->new( 'x' => $ref, 'y' => $ref );
    my $pack = $double->pack;
    ok( $pack,              "Object packs with DisableCycleDetection trait");
    ok( DoubleNoCycle->unpack( $pack ),
                            "   Unpacked again" );
}