@Test
  public void deterministicUpgradeUnencrypted() throws Exception {
    // Check that a group that contains only random keys has its HD chain created using the private
    // key bytes of
    // the oldest random key, so upgrading the same wallet twice gives the same outcome.
    group = new KeyChainGroup(params);
    group.setLookaheadSize(LOOKAHEAD_SIZE); // Don't want slow tests.
    ECKey key1 = new ECKey();
    Utils.rollMockClock(86400);
    ECKey key2 = new ECKey();
    group.importKeys(key2, key1);

    List<Protos.Key> protobufs = group.serializeToProtobuf();
    group.upgradeToDeterministic(0, null);
    assertFalse(group.isDeterministicUpgradeRequired());
    DeterministicKey dkey1 = group.freshKey(KeyChain.KeyPurpose.RECEIVE_FUNDS);
    DeterministicSeed seed1 = group.getActiveKeyChain().getSeed();
    assertNotNull(seed1);

    group = KeyChainGroup.fromProtobufUnencrypted(params, protobufs);
    group.upgradeToDeterministic(0, null); // Should give same result as last time.
    DeterministicKey dkey2 = group.freshKey(KeyChain.KeyPurpose.RECEIVE_FUNDS);
    DeterministicSeed seed2 = group.getActiveKeyChain().getSeed();
    assertEquals(seed1, seed2);
    assertEquals(dkey1, dkey2);

    // Check we used the right (oldest) key despite backwards import order.
    byte[] truncatedBytes = Arrays.copyOfRange(key1.getSecretBytes(), 0, 16);
    assertArrayEquals(seed1.getEntropyBytes(), truncatedBytes);
  }
 @Test
 public void deterministicUpgradeRotating() throws Exception {
   group = new KeyChainGroup(params);
   group.setLookaheadSize(LOOKAHEAD_SIZE); // Don't want slow tests.
   long now = Utils.currentTimeSeconds();
   ECKey key1 = new ECKey();
   Utils.rollMockClock(86400);
   ECKey key2 = new ECKey();
   Utils.rollMockClock(86400);
   ECKey key3 = new ECKey();
   group.importKeys(key2, key1, key3);
   group.upgradeToDeterministic(now + 10, null);
   DeterministicSeed seed = group.getActiveKeyChain().getSeed();
   assertNotNull(seed);
   // Check we used the right key: oldest non rotating.
   byte[] truncatedBytes = Arrays.copyOfRange(key2.getSecretBytes(), 0, 16);
   assertArrayEquals(seed.getEntropyBytes(), truncatedBytes);
 }