### Question:
IbanGenerationService { private String generateIban(CountryCode countryCode, String bankCode, long accountNr) { int accountNumberLength = BbanStructure.forCountry(countryCode).getEntries().stream() .filter(e -> e.getEntryType().equals(account_number)) .findFirst() .map(BbanStructureEntry::getLength) .orElse(0); String formatParam = "%0" + accountNumberLength + "d"; String accountNumber = String.format(formatParam, accountNr); return new Iban.Builder() .countryCode(countryCode) .bankCode(bankCode) .accountNumber(accountNumber) .buildRandom() .toString(); }  String generateNextIban(String tppId); String generateIbanForNisp(DataPayload payload, String iban); Map<CountryCode, String> getCountryCodes(); BankCodeStructure getBankCodeStructure(CountryCode code);  }### Answer:
@Test void generateIban() { stubGetByIdCall(TPP_ID, Collections.EMPTY_LIST, UserRoleTO.STAFF); String iban = generationService.generateNextIban(TPP_ID); boolean isIbanValid = IBANValidator.getInstance().isValid(iban); assertTrue(isIbanValid); }