Object Oriented Testing - Example use Test::MockObject; my $mock = Test::MockObject->new(); $mock->fake_module( 'Credit::Card::Backend' ); $mock->fake_new( 'Credit::Card::Backend' ); $mock->set_true( 'authorize_card' ); $mock->set_true( 'finalize_payment' ); use Shopping::Cart; my $cardnum = '4444333322221111'; my $expdate = '09/10'; my $product = 'MX5 Stealth kitten'; my $cart = Shopping::Cart->new(); ok( $cart->add_by_name(product_name => $product); ok( $cart->checkout( expdate => $expdate, cardnum => $cardno, ) );