long bHi = b >>> 32; // < 2^31
        long aLo = a & 0xFFFFFFFFL; // < 2^32
        long bLo = b & 0xFFFFFFFFL; // < 2^32

        /*
         * a * b == aHi * bHi * 2^64 + (aHi * bLo + aLo * bHi) * 2^32 + aLo * bLo.
         *       == (aHi * bHi * 2^32 + aHi * bLo + aLo * bHi) * 2^32 + aLo * bLo
         *

    testRotate(new byte[] {1, 2, 3}, -3, new byte[] {1, 2, 3});
    testRotate(new byte[] {1, 2, 3}, -2, new byte[] {3, 1, 2});
    testRotate(new byte[] {1, 2, 3}, -1, new byte[] {2, 3, 1});
    testRotate(new byte[] {1, 2, 3}, 0, new byte[] {1, 2, 3});
    testRotate(new byte[] {1, 2, 3}, 1, new byte[] {3, 1, 2});
    testRotate(new byte[] {1, 2, 3}, 2, new byte[] {2, 3, 1});
    testRotate(new byte[] {1, 2, 3}, 3, new byte[] {1, 2, 3});

   * interpreted as a normal bit, and all other bits are treated as usual.
   *
   * <p>If the argument is nonnegative, the returned result will be equal to {@code bits},
   * otherwise, the result will be equal to {@code 2^32 + bits}.
   *
   * <p>To represent unsigned decimal constants, consider {@link #valueOf(long)} instead.
   *
   * @since 14.0
   */
  public static UnsignedInteger fromIntBits(int bits) {

    testRotate(new char[] {'1', '2', '3'}, -2, new char[] {'3', '1', '2'});
    testRotate(new char[] {'1', '2', '3'}, -1, new char[] {'2', '3', '1'});
    testRotate(new char[] {'1', '2', '3'}, 0, new char[] {'1', '2', '3'});
    testRotate(new char[] {'1', '2', '3'}, 1, new char[] {'3', '1', '2'});
    testRotate(new char[] {'1', '2', '3'}, 2, new char[] {'2', '3', '1'});

    }.test();
  }

  public void testDoubler() {
    Iterable<Integer> doubled =
        new Iterable<Integer>() {
          @Override
          public Iterator<Integer> iterator() {
            return newDoubler(2, 32);
          }
        };
    assertThat(doubled).containsExactly(2, 4, 8, 16, 32).inOrder();
  }

  public void testSampleCode() {
    Iterable<Integer> actual =
        new Iterable<Integer>() {

    testRotate(new double[] {1, 2, 3}, -2, new double[] {3, 1, 2});
    testRotate(new double[] {1, 2, 3}, -1, new double[] {2, 3, 1});
    testRotate(new double[] {1, 2, 3}, 0, new double[] {1, 2, 3});
    testRotate(new double[] {1, 2, 3}, 1, new double[] {3, 1, 2});
    testRotate(new double[] {1, 2, 3}, 2, new double[] {2, 3, 1});
    testRotate(new double[] {1, 2, 3}, 3, new double[] {1, 2, 3});

    testRotate(new int[] {1, 2, 3}, -3, new int[] {1, 2, 3});
    testRotate(new int[] {1, 2, 3}, -2, new int[] {3, 1, 2});
    testRotate(new int[] {1, 2, 3}, -1, new int[] {2, 3, 1});
    testRotate(new int[] {1, 2, 3}, 0, new int[] {1, 2, 3});
    testRotate(new int[] {1, 2, 3}, 1, new int[] {3, 1, 2});
    testRotate(new int[] {1, 2, 3}, 2, new int[] {2, 3, 1});
    testRotate(new int[] {1, 2, 3}, 3, new int[] {1, 2, 3});

    testRotate(new double[] {1, 2, 3}, -2, new double[] {3, 1, 2});
    testRotate(new double[] {1, 2, 3}, -1, new double[] {2, 3, 1});
    testRotate(new double[] {1, 2, 3}, 0, new double[] {1, 2, 3});
    testRotate(new double[] {1, 2, 3}, 1, new double[] {3, 1, 2});
    testRotate(new double[] {1, 2, 3}, 2, new double[] {2, 3, 1});
    testRotate(new double[] {1, 2, 3}, 3, new double[] {1, 2, 3});

    testRotate(new long[] {1, 2, 3}, -3, new long[] {1, 2, 3});
    testRotate(new long[] {1, 2, 3}, -2, new long[] {3, 1, 2});
    testRotate(new long[] {1, 2, 3}, -1, new long[] {2, 3, 1});
    testRotate(new long[] {1, 2, 3}, 0, new long[] {1, 2, 3});
    testRotate(new long[] {1, 2, 3}, 1, new long[] {3, 1, 2});
    testRotate(new long[] {1, 2, 3}, 2, new long[] {2, 3, 1});
    testRotate(new long[] {1, 2, 3}, 3, new long[] {1, 2, 3});

    testRotate(new short[] {1, 2, 3}, -3, new short[] {1, 2, 3});
    testRotate(new short[] {1, 2, 3}, -2, new short[] {3, 1, 2});
    testRotate(new short[] {1, 2, 3}, -1, new short[] {2, 3, 1});
    testRotate(new short[] {1, 2, 3}, 0, new short[] {1, 2, 3});
    testRotate(new short[] {1, 2, 3}, 1, new short[] {3, 1, 2});
    testRotate(new short[] {1, 2, 3}, 2, new short[] {2, 3, 1});
    testRotate(new short[] {1, 2, 3}, 3, new short[] {1, 2, 3});