1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
|
use strict;
use warnings;
use Test::More;
use Test::Exception;
use Class::MOP;
{
package BankAccount;
use strict;
use warnings;
use metaclass;
use Carp 'confess';
BankAccount->meta->add_attribute(
'balance' => (
accessor => 'balance',
init_arg => 'balance',
default => 0
)
);
sub new { (shift)->meta->new_object(@_) }
sub deposit {
my ( $self, $amount ) = @_;
$self->balance( $self->balance + $amount );
}
sub withdraw {
my ( $self, $amount ) = @_;
my $current_balance = $self->balance();
( $current_balance >= $amount )
|| confess "Account overdrawn";
$self->balance( $current_balance - $amount );
}
package CheckingAccount;
use strict;
use warnings;
use metaclass;
use base 'BankAccount';
CheckingAccount->meta->add_attribute(
'overdraft_account' => (
accessor => 'overdraft_account',
init_arg => 'overdraft',
)
);
CheckingAccount->meta->add_before_method_modifier(
'withdraw' => sub {
my ( $self, $amount ) = @_;
my $overdraft_amount = $amount - $self->balance();
if ( $overdraft_amount > 0 ) {
$self->overdraft_account->withdraw($overdraft_amount);
$self->deposit($overdraft_amount);
}
}
);
::throws_ok(
sub {
CheckingAccount->meta->add_before_method_modifier(
'does_not_exist' => sub { } );
},
qr/\QThe method 'does_not_exist' was not found in the inheritance hierarchy for CheckingAccount/
);
::ok( CheckingAccount->meta->has_method('withdraw'),
'... checking account now has a withdraw method' );
::isa_ok( CheckingAccount->meta->get_method('withdraw'),
'Class::MOP::Method::Wrapped' );
::isa_ok( BankAccount->meta->get_method('withdraw'),
'Class::MOP::Method' );
CheckingAccount->meta->add_method( foo => sub { 'foo' } );
CheckingAccount->meta->add_before_method_modifier( foo => sub { 'wrapped' } );
::isa_ok( CheckingAccount->meta->get_method('foo'),
'Class::MOP::Method::Wrapped' );
}
my $savings_account = BankAccount->new( balance => 250 );
isa_ok( $savings_account, 'BankAccount' );
is( $savings_account->balance, 250, '... got the right savings balance' );
lives_ok {
$savings_account->withdraw(50);
}
'... withdrew from savings successfully';
is( $savings_account->balance, 200,
'... got the right savings balance after withdrawal' );
dies_ok {
$savings_account->withdraw(250);
}
'... could not withdraw from savings successfully';
$savings_account->deposit(150);
is( $savings_account->balance, 350,
'... got the right savings balance after deposit' );
my $checking_account = CheckingAccount->new(
balance => 100,
overdraft => $savings_account
);
isa_ok( $checking_account, 'CheckingAccount' );
isa_ok( $checking_account, 'BankAccount' );
is( $checking_account->overdraft_account, $savings_account,
'... got the right overdraft account' );
is( $checking_account->balance, 100, '... got the right checkings balance' );
lives_ok {
$checking_account->withdraw(50);
}
'... withdrew from checking successfully';
is( $checking_account->balance, 50,
'... got the right checkings balance after withdrawal' );
is( $savings_account->balance, 350,
'... got the right savings balance after checking withdrawal (no overdraft)'
);
lives_ok {
$checking_account->withdraw(200);
}
'... withdrew from checking successfully';
is( $checking_account->balance, 0,
'... got the right checkings balance after withdrawal' );
is( $savings_account->balance, 200,
'... got the right savings balance after overdraft withdrawal' );
done_testing;
|
