### Question:
NationalAccountIdValidator extends BankValidator { @Override public ValidationResult validate(String input) { int length; switch (countryCode) { case "AR": length = 22; if (isNumberWithFixedLength(input, length)) return super.validate(input); else { String nationalAccountIdLabel = BankUtil.getNationalAccountIdLabel(countryCode); return new ValidationResult(false, Res.get("validation.nationalAccountId", nationalAccountIdLabel, length)); } default: return super.validate(input); } } NationalAccountIdValidator(String countryCode); @Override ValidationResult validate(String input);  }### Answer:
@Test public void testValidationForArgentina(){ NationalAccountIdValidator validator = new NationalAccountIdValidator("AR"); assertTrue(validator.validate("2850590940090418135201").isValid); final String wrongNationalAccountId = "285059094009041813520"; assertFalse(validator.validate(wrongNationalAccountId).isValid); assertEquals("CBU number must consist of 22 numbers.", validator.validate(wrongNationalAccountId).errorMessage); }