@Test
 public void testAliasTo() throws Exception {
   final ByteBuffer key = ByteBuffer.wrap("abc".getBytes());
   key.mark();
   final ByteBuffer alias = ByteBuffer.wrap("def".getBytes());
   alias.mark();
   ((SignatureVerifierWithIdentityStore) signatureVerifier).aliasTo(key, alias);
   final HashIdentity retrieved = identityDatastore.get(key);
   assertNotNull(retrieved);
   assertEquals(key, retrieved.getHash());
   assertTrue(retrieved.getHashIdentity() instanceof ByteBuffer);
   assertEquals(alias, retrieved.getHashIdentity());
 }