path: root/test/option.cc

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

struct checker {
  static unsigned cnt;

  checker() {
    ++cnt;
  }
  checker(const checker&) {
    ++cnt;
  }
  checker(checker&&) noexcept {
    ++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;
}