public function testGetPostage()
 {
     $country = new Country();
     $area = new Area();
     $instance = new FlatFeeDelivery();
     $area->setPostage(2.0);
     $country->setArea($area);
     $this->assertEquals($instance->getPostage($country), 2.0);
     $area->setPostage(null);
     $country->setArea($area);
     $this->assertEquals($instance->getPostage($country), 0.0);
 }