017_add_method_modifier.t [plain text]
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;