The random test does not properly generate only alphanumeric values, This is my suggestion to address that issue

OK! I added the random tests, I hope my translate will be approved otherwise let me know your observations

But are they random test cases? Please look at the function for generating a random string in C++ below:

std::string random_string(size_t length) {
  auto randchar = []() -> char {
    static auto& charset = "0123456789"
                           "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
                           "abcdefghijklmnopqrstuvwxyz";
    static const size_t max_index = (sizeof(charset) - 1);

    thread_local static std::random_device rd;
    thread_local static std::mt19937 rg(rd());
    thread_local static std::uniform_int_distribution<int> pick(0, max_index);
    
    //return charset[rand() % max_index];
    return charset[pick(rg)];
  };

Completed! 👍 I added 4 new tests

Thank you for the translation to Rust.
Can you please random tests as well?