@Override
   public int[] toIntArray() {
      int[] array = new int[1];
      array[0] = value;
      return array;
   }
@Test
   public void testToIntArray() throws Exception {
      IntSet sis = new SingletonIntSet(3);
      int[] array = sis.toIntArray();

      assertArrayEquals(new int[]{3}, array);
   }