Calling a Rust crate from Ruby minitest

iban_test.rb

require_relative 'test_helper'

require 'helix_runtime'
require 'etl-test/native'

class MyTest < Minitest::Test
  def test_valid
    assert_equal true, IbanChecker.check('TL380080012345678910157')
  end
  
  def test_invalid_country
    assert_equal false, IbanChecker.check('AD54BD012030200359100100')
  end
  
  def test_invalid_length
    assert_equal false, IbanChecker.check('DE4')
  end
end

lib.rs

#[macro_use]
extern crate helix;
extern crate iban;

use std::str;
use iban::Iban;
use iban::BbanResult;

ruby! {
    class IbanChecker {
        def check(iban_number : String) -> bool {
            let account = iban_number.parse::<Iban>();
            
            let account = match account {
                Ok(iban) => iban,
                Err(_error) => {
                    return false;
                } 
            };
            if account.validate_bban() == BbanResult::Valid {
                return true;
            } else {
                return false;
            }
        }
    }
}