code: private byte[] generateAesIv() {
          byte[] bytes = new byte[16];
          if (!testMode) {
              SecureRandom random = new SecureRandom();
              random.nextBytes(bytes);
          } else {
              bytes = "TEST1234TEST1234".getBytes(MESSAGE_ENCODING);
          }
          return bytes;
      }
docs: Generates initialization vector for AES encryption.
  
  @return Random IV or pre-defined value for test mode.