@Test
 public void providesSlotLocation() {
   Item item = getRegularItem();
   inventory.executeAddItem(InventorySlot.HEAD, item);
   ItemLocation loc = inventory.getSlotLocation(InventorySlot.HEAD);
   assertNotNull(loc);
   assertSame(item, loc.get());
 }
 @Test
 public void locationOfItemFindsItem() {
   Item item = getRegularItem();
   inventory.executeAddItem(InventorySlot.HEAD, item);
   ItemLocation loc = inventory.getLocationOf(item);
   assertNotNull(loc);
   assertSame(item, loc.get());
   assertEquals(InventorySlot.HEAD.ordinal(), loc.getIndex());
   assertSame(inventory, loc.getCylinder());
 }