@Override
 @Test
 public void collectShort() {
   MutableBag<Integer> integers = UnmodifiableBag.of(HashBag.newBagWith(1, 2, 2, 3, 3, 3));
   Assert.assertEquals(
       ShortHashBag.newBagWith((short) 1, (short) 2, (short) 2, (short) 3, (short) 3, (short) 3),
       integers.collectShort(PrimitiveFunctions.unboxIntegerToShort()));
 }