@Test
public void testMakeRand()
    throws NoSuchAlgorithmException {

    byte[] r = Digest.makeRand();
    assertFalse("makeRand failed - hash of all zeros",
                Arrays.equals(r,
                Digest.digest(new byte[Digest.HASH_SIZE_BYTES])));
    if (r.length != Digest.HASH_SIZE_BYTES) {
        fail("Digest of random number failed - wrong length.");
    }
}