### Question:
Wallet { public boolean unlockAccount(UscAddress addr, String passphrase, long duration) { long ending = System.currentTimeMillis() + duration; boolean unlocked = unlockAccount(addr, passphrase); if (unlocked) { synchronized (accessLock) { unlocksTimeouts.put(addr, ending); } } return unlocked; } Wallet(KeyValueDataSource keyDS); List<byte[]> getAccountAddresses(); String[] getAccountAddressesAsHex(); UscAddress addAccount(); UscAddress addAccount(String passphrase); UscAddress addAccount(Account account); Account getAccount(UscAddress addr); Account getAccount(UscAddress addr, String passphrase); boolean unlockAccount(UscAddress addr, String passphrase, long duration); boolean unlockAccount(UscAddress addr, String passphrase); boolean lockAccount(UscAddress addr); byte[] addAccountWithSeed(String seed); byte[] addAccountWithPrivateKey(byte[] privateKeyBytes); byte[] addAccountWithPrivateKey(byte[] privateKeyBytes, String passphrase);  }### Answer:
@Test public void unlockNonexistentAccount() { Wallet wallet = WalletFactory.createWallet(); UscAddress addr = new UscAddress("0x0000000000000000000000000000000000000023"); Assert.assertFalse(wallet.unlockAccount(addr, "passphrase")); }