path: root/test/option.cc

#include <option.h>
#include <cstdlib>
#include <cstdio>

struct Checker {
  static unsigned cnt;

  Checker() {
    ++cnt;
  }
  Checker(const Checker&) {
    ++cnt;
  }
  Checker(Checker&&) {
    ++cnt;
  }
  ~Checker() {
    --cnt;
  }
};

unsigned Checker::cnt = 0;

int main() {
  using option::option;

  auto check_cnt = [](unsigned expect) {
      if (expect != Checker::cnt) {
          std::printf("Checker: expect=%u cnt=%u\n", expect, Checker::cnt);
          std::abort();
      }

  };

  {
      option<int> o1;
      option<int> o2{::option::none{}};

      assert(!o1.has_value());
      assert(!o2.has_value());
  }

  // Assume we start test with cnt=0.
  check_cnt(0);

  {
      option<Checker> o1(Checker{});
      // copy construct
      option<Checker> o2 = o1;
      // move construct
      option<Checker> o3 = o1.take();

      assert(!o1.has_value());
      assert(o2.has_value());
      assert(o3.has_value());

      // move option
      option<Checker> o4 = std::move(o2);

      assert(!o2.has_value());
      assert(o4.has_value());

      // take reference to inner
      auto x = o3.value();
      // take ownership of inner
      auto y = o4.take();

      assert(!o1.has_value());
      assert(!o2.has_value());
      assert(o3.has_value());
      assert(!o4.has_value());
  }

  // Expect to finish test with cnt=0.
  check_cnt(0);

  {
      option<Checker> o1;
      assert(!o1.has_value());

      o1.emplace();
      assert(o1.has_value());
  }

  // Expect to finish test with cnt=0.
  check_cnt(0);

  return 0;
}