attach_singleton.t revision 1.1.1.1 
1#!./perl -w
2#
3#  Copyright 2005, Adam Kennedy.
4#
5#  You may redistribute only under the same terms as Perl 5, as specified
6#  in the README file that comes with the distribution.
7#
8
9# Tests freezing/thawing structures containing Singleton objects,
10# which should see both structs pointing to the same object.
11
12sub BEGIN {
13    unshift @INC, 't';
14    require Config; import Config;
15    if ($ENV{PERL_CORE} and $Config{'extensions'} !~ /\bStorable\b/) {
16        print "1..0 # Skip: Storable was not built\n";
17        exit 0;
18    }
19}
20
21use Test::More tests => 11;
22use Storable ();
23
24# Get the singleton
25my $object = My::Singleton->new;
26isa_ok( $object, 'My::Singleton' );
27
28# Confirm (for the record) that the class is actually a Singleton
29my $object2 = My::Singleton->new;
30isa_ok( $object2, 'My::Singleton' );
31is( "$object", "$object2", 'Class is a singleton' );
32
33############
34# Main Tests
35
36my $struct = [ 1, $object, 3 ];
37
38# Freeze the struct
39my $frozen = Storable::freeze( $struct );
40ok( (defined($frozen) and ! ref($frozen) and length($frozen)), 'freeze returns a string' );
41
42# Thaw the struct
43my $thawed = Storable::thaw( $frozen );
44
45# Now it should look exactly like the original
46is_deeply( $struct, $thawed, 'Struct superficially looks like the original' );
47
48# ... EXCEPT that the Singleton should be the same instance of the object
49is( "$struct->[1]", "$thawed->[1]", 'Singleton thaws correctly' );
50
51# We can also test this empirically
52$struct->[1]->{value} = 'Goodbye cruel world!';
53is_deeply( $struct, $thawed, 'Empiric testing corfirms correct behaviour' );
54
55# End Tests
56###########
57
58package My::Singleton;
59
60my $SINGLETON = undef;
61
62sub new {
63	$SINGLETON or
64	$SINGLETON = bless { value => 'Hello World!' }, $_[0];
65}
66
67sub STORABLE_freeze {
68	my $self = shift;
69
70	# We don't actually need to return anything, but provide a null string
71	# to avoid the null-list-return behaviour.
72	return ('foo');
73}
74
75sub STORABLE_attach {
76	my ($class, $clone, $string) = @_;
77	Test::More::ok( ! ref $class, 'STORABLE_attach passed class, and not an object' );
78	Test::More::is( $class, 'My::Singleton', 'STORABLE_attach is passed the correct class name' );
79	Test::More::is( $clone, 0, 'We are not in a dclone' );
80	Test::More::is( $string, 'foo', 'STORABLE_attach gets the string back' );
81
82	# Get the Singleton object and return it
83	return $class->new;
84}
85