@Test
 public void testSubList() {
   int i = RandomPicker.getInt(SIZE / 2);
   List<Integer> subList = list.subList(i, i + SIZE / 2);
   for (int integer : subList) {
     assertEquals(i++, integer);
   }
 }
 private int randomInt() {
   return RandomPicker.getInt(SIZE);
 }