### Question:
Account { public boolean addBalance(BigInteger value){ BigInteger result = balance.add(value); if (result.compareTo(BigInteger.ZERO) < 0) { return false; } balance = result; this.dirty = true; return true; } Account(byte[] protoBuf);  Account(BigInteger balance, byte[] storageRoot, byte[] binHash, byte[] permissionRoot); byte[] getEncoded(); boolean addBalance(BigInteger value); AccountTypeEnum getAccountType(); boolean isEmpty(); void untouch(); boolean isContractExist(); byte[] getBin(); void setBin(byte[] bin); void setStorage(byte[] key, byte[] value); byte[] getStorage(byte[] key); Map<ByteArrayWrapper, byte[]> getStorageMap(); void setPermissionRoot(byte[] permissionRoot); BigInteger getBalance(); byte[] getStorageRoot(); void setStorageRoot(byte[] storageRoot); byte[] getBinHash(); byte[] getPermissionRoot(); boolean isDirty();  }### Answer:
@Test public void addBalance() { Account account = this.init(); BigInteger addBalance = new BigInteger("-1"); account.addBalance(addBalance); Assert.assertEquals(account.getBalance().toString(),balance.add(addBalance).toString()); }