@Test
 public void collectByte() {
   ImmutableCollection<Integer> integers = this.classUnderTest();
   ImmutableByteCollection immutableCollection =
       integers.collectByte(PrimitiveFunctions.unboxIntegerToByte());
   Verify.assertSize(integers.size(), immutableCollection);
   Assert.assertEquals(integers, immutableCollection.collect(Integer::valueOf));
 }