function testReservation()
 {
     $item = new Item('Perfect PHP', 3600, '2010/11', 2);
     $this->assertFalse($item->reservation('1'));
     $this->assertFalse($item->reservation(1.1));
     $this->assertTrue($item->reservation(1));
     $this->assertIdentical($item->getStock(), 1);
     $item = new Item('Perfect PHP', 3600, '2010/11', 2);
     $this->assertTrue($item->reservation(2));
     $this->assertIdentical($item->getStock(), 0);
     $item = new Item('Perfect PHP', 3600, '2010/11', 2);
     $this->assertFalse($item->reservation(3));
     $this->assertIdentical($item->getStock(), 2);
 }