text: // Copyright (c) 2018 Jyocoin Project, Derived from 2018, The Monero Project
  //
  // All rights reserved.
  //
  // Redistribution and use in source and binary forms, with or without modification, are
  // permitted provided that the following conditions are met:
  //
  // 1. Redistributions of source code must retain the above copyright notice, this list of
  //    conditions and the following disclaimer.
  //
  // 2. Redistributions in binary form must reproduce the above copyright notice, this list
  //    of conditions and the following disclaimer in the documentation and/or other
  //    materials provided with the distribution.
  //
  // 3. Neither the name of the copyright holder nor the names of its contributors may be
  //    used to endorse or promote products derived from this software without specific
  //    prior written permission.
  //
  // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
  // EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  // MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
  // THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  // PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  // INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  // STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
  // THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  
  #include <gtest/gtest.h>
  
  #include <boost/algorithm/string/predicate.hpp>
  #include <boost/utility/string_ref.hpp>
  #include <string>
  #include <system_error>
  #include <type_traits>
  
  #include "common/expect.h"
  
  namespace
  {
      struct move_only;
      struct throw_construct;
      struct throw_copies;
      struct throw_moves;
  
      struct move_only
      {
          move_only() = default;
          move_only(move_only const&) = delete;
          move_only(move_only&&) = default;
          ~move_only() = default;
          move_only& operator=(move_only const&) = delete;
          move_only& operator=(move_only&&) = default;
      };
  
      struct throw_construct
      {
          throw_construct() {}
          throw_construct(int) {}
          throw_construct(throw_construct const&) = default;
          throw_construct(throw_construct&&) = default;
          ~throw_construct() = default;
          throw_construct& operator=(throw_construct const&) = default;
          throw_construct& operator=(throw_construct&&) = default;
      };
  
      struct throw_copies
      {
          throw_copies() noexcept {}
          throw_copies(throw_copies const&) {}
          throw_copies(throw_copies&&) = default;
          ~throw_copies() = default;
          throw_copies& operator=(throw_copies const&) { return *this; }
          throw_copies& operator=(throw_copies&&) = default;
          bool operator==(throw_copies const&) noexcept { return true; }
          bool operator==(throw_moves const&) noexcept { return true; }
      };
  
      struct throw_moves
      {
          throw_moves() noexcept {}
          throw_moves(throw_moves const&) = default;
          throw_moves(throw_moves&&) {}
          ~throw_moves() = default;
          throw_moves& operator=(throw_moves const&) = default;
          throw_moves& operator=(throw_moves&&) { return *this; }
          bool operator==(throw_moves const&) { return true; }
          bool operator==(throw_copies const&) { return true; }
      };
  
      template<typename T>
      void construction_bench()
      {
          EXPECT_TRUE(std::is_copy_constructible<expect<T>>());
          EXPECT_TRUE(std::is_move_constructible<expect<T>>());
          EXPECT_TRUE(std::is_copy_assignable<expect<T>>());
          EXPECT_TRUE(std::is_move_assignable<expect<T>>());
          EXPECT_TRUE(std::is_destructible<expect<T>>());
      }
  
      template<typename T>
      void noexcept_bench()
      {
          EXPECT_TRUE(std::is_nothrow_copy_constructible<expect<T>>());
          EXPECT_TRUE(std::is_nothrow_move_constructible<expect<T>>());
          EXPECT_TRUE(std::is_nothrow_copy_assignable<expect<T>>());
          EXPECT_TRUE(std::is_nothrow_move_assignable<expect<T>>());
          EXPECT_TRUE(std::is_nothrow_destructible<expect<T>>());
  
          EXPECT_TRUE(noexcept(bool(std::declval<expect<T>>())));
          EXPECT_TRUE(noexcept(std::declval<expect<T>>().has_error()));
          EXPECT_TRUE(noexcept(std::declval<expect<T>>().error()));
          EXPECT_TRUE(noexcept(std::declval<expect<T>>().equal(std::declval<expect<T>>())));
          EXPECT_TRUE(noexcept(std::declval<expect<T>>() == std::declval<expect<T>>()));
          EXPECT_TRUE(noexcept(std::declval<expect<T>>() != std::declval<expect<T>>()));
      }
  
      template<typename T>
      void conversion_bench()
      {
          EXPECT_TRUE((std::is_convertible<std::error_code, expect<T>>()));
          EXPECT_TRUE((std::is_convertible<std::error_code&&, expect<T>>()));
          EXPECT_TRUE((std::is_convertible<std::error_code&, expect<T>>()));
          EXPECT_TRUE((std::is_convertible<std::error_code const&, expect<T>>()));
  
          EXPECT_TRUE((std::is_constructible<expect<T>, std::error_code>()));
          EXPECT_TRUE((std::is_constructible<expect<T>, std::error_code&&>()));
          EXPECT_TRUE((std::is_constructible<expect<T>, std::error_code&>()));
          EXPECT_TRUE((std::is_constructible<expect<T>, std::error_code const&>()));
      }
  }
  
  
  TEST(Expect, Constructions)
  {
      construction_bench<void>();
      construction_bench<int>();
  
      EXPECT_TRUE(std::is_constructible<expect<void>>());
  
      EXPECT_TRUE((std::is_constructible<expect<throw_construct>, expect<int>>()));
  
      EXPECT_TRUE(std::is_move_constructible<expect<move_only>>());
      EXPECT_TRUE(std::is_move_assignable<expect<move_only>>());
  }
  
  TEST(Expect, Conversions)
  {
      struct implicit { implicit(int) {} };
      struct explicit_only { explicit explicit_only(int) {} };
  
      conversion_bench<void>();
      conversion_bench<int>();
  
      EXPECT_TRUE((std::is_convertible<int, expect<int>>()));
      EXPECT_TRUE((std::is_convertible<int&&, expect<int>>()));
      EXPECT_TRUE((std::is_convertible<int&, expect<int>>()));
      EXPECT_TRUE((std::is_convertible<int const, expect<int>>()));
      EXPECT_TRUE((std::is_convertible<expect<unsigned>, expect<int>>()));
      EXPECT_TRUE((std::is_convertible<expect<unsigned>&&, expect<int>>()));
      EXPECT_TRUE((std::is_convertible<expect<unsigned>&, expect<int>>()));
      EXPECT_TRUE((std::is_convertible<expect<unsigned> const&, expect<int>>()));
      EXPECT_TRUE((std::is_convertible<expect<int>, expect<implicit>>()));
      EXPECT_TRUE((std::is_convertible<expect<int>&&, expect<implicit>>()));
      EXPECT_TRUE((std::is_convertible<expect<int>&, expect<implicit>>()));
      EXPECT_TRUE((std::is_convertible<expect<int> const&, expect<implicit>>()));
      EXPECT_TRUE(!(std::is_convertible<expect<int>, expect<explicit_only>>()));
      EXPECT_TRUE(!(std::is_convertible<expect<int>&&, expect<explicit_only>>()));
      EXPECT_TRUE(!(std::is_convertible<expect<int>&, expect<explicit_only>>()));
      EXPECT_TRUE(!(std::is_convertible<expect<int> const&, expect<explicit_only>>()));
  
      EXPECT_TRUE((std::is_constructible<expect<int>, int>()));
      EXPECT_TRUE((std::is_constructible<expect<int>, int&&>()));
      EXPECT_TRUE((std::is_constructible<expect<int>, int&>()));
      EXPECT_TRUE((std::is_constructible<expect<int>, int const&>()));
      EXPECT_TRUE((std::is_constructible<expect<int>, expect<unsigned>>()));
      EXPECT_TRUE((std::is_constructible<expect<int>, expect<unsigned>&&>()));
      EXPECT_TRUE((std::is_constructible<expect<int>, expect<unsigned>&>()));
      EXPECT_TRUE((std::is_constructible<expect<int>, expect<unsigned> const&>()));
      EXPECT_TRUE((std::is_constructible<expect<implicit>, expect<int>>()));
      EXPECT_TRUE((std::is_constructible<expect<implicit>, expect<int>&&>()));
      EXPECT_TRUE((std::is_constructible<expect<implicit>, expect<int>&>()));
      EXPECT_TRUE((std::is_constructible<expect<implicit>, expect<int> const&>()));
      EXPECT_TRUE(!(std::is_constructible<expect<explicit_only>, expect<int>>()));
      EXPECT_TRUE(!(std::is_constructible<expect<explicit_only>, expect<int>&&>()));
      EXPECT_TRUE(!(std::is_constructible<expect<explicit_only>, expect<int>&>()));
      EXPECT_TRUE(!(std::is_constructible<expect<explicit_only>, expect<int> const&>()));
  
      EXPECT_EQ(expect<int>{expect<short>{100}}.value(), 100);
  
      expect<std::string> val1{std::string{}};
      expect<const char*> val2{"foo"};
  
      EXPECT_EQ(val1.value(), std::string{});
      EXPECT_EQ(val2.value(), std::string{"foo"});
  
      const expect<std::string> val3{val2};
  
      EXPECT_EQ(val1.value(), std::string{});
      EXPECT_EQ(val2.value(), std::string{"foo"});
      EXPECT_EQ(val3.value(), std::string{"foo"});
  
      val1 = val2;
  
      EXPECT_EQ(val1.value(), "foo");
      EXPECT_EQ(val2.value(), std::string{"foo"});
      EXPECT_EQ(val3.value(), "foo");
  }
  
  TEST(Expect, NoExcept)
  {
      noexcept_bench<void>();
      noexcept_bench<int>();
  
      EXPECT_TRUE(std::is_nothrow_constructible<expect<void>>());
  
      EXPECT_TRUE((std::is_nothrow_constructible<expect<int>, int>()));
      EXPECT_TRUE((std::is_nothrow_constructible<expect<int>, expect<unsigned>>()));
      EXPECT_TRUE((std::is_nothrow_constructible<expect<int>, expect<unsigned>&&>()));
      EXPECT_TRUE((std::is_nothrow_constructible<expect<int>, expect<unsigned>&>()));
      EXPECT_TRUE((std::is_nothrow_constructible<expect<int>, expect<unsigned> const&>()));
  
      EXPECT_TRUE(noexcept(expect<int>{std::declval<expect<unsigned>&&>()}));
      EXPECT_TRUE(noexcept(expect<int>{std::declval<expect<unsigned> const&>()}));
      EXPECT_TRUE(noexcept(std::declval<expect<int>>().has_value()));
      EXPECT_TRUE(noexcept(*std::declval<expect<int>>()));
      EXPECT_TRUE(noexcept(std::declval<expect<int>>().equal(std::declval<expect<unsigned>>())));
      EXPECT_TRUE(noexcept(std::declval<expect<unsigned>>().equal(std::declval<expect<int>>())));
      EXPECT_TRUE(noexcept(std::declval<expect<int>>().equal(0)));
      EXPECT_TRUE(noexcept(std::declval<expect<int>>() == std::declval<expect<unsigned>>()));
      EXPECT_TRUE(noexcept(std::declval<expect<unsigned>>() == std::declval<expect<int>>()));
      EXPECT_TRUE(noexcept(std::declval<expect<int>>() == 0));
      EXPECT_TRUE(noexcept(0 == std::declval<expect<int>>()));
      EXPECT_TRUE(noexcept(std::declval<expect<int>>() != std::declval<expect<unsigned>>()));
      EXPECT_TRUE(noexcept(std::declval<expect<unsigned>>() != std::declval<expect<int>>()));
      EXPECT_TRUE(noexcept(std::declval<expect<int>>() != 0));
      EXPECT_TRUE(noexcept(0 != std::declval<expect<int>>()));
  
      EXPECT_TRUE((std::is_nothrow_constructible<expect<throw_construct>, std::error_code>()));
      EXPECT_TRUE((std::is_nothrow_constructible<expect<throw_construct>, std::error_code&&>()));
      EXPECT_TRUE((std::is_nothrow_constructible<expect<throw_construct>, std::error_code&>()));
      EXPECT_TRUE((std::is_nothrow_constructible<expect<throw_construct>, std::error_code const&>()));
      EXPECT_TRUE((std::is_nothrow_constructible<expect<throw_construct>, throw_construct>()));
      EXPECT_TRUE((std::is_nothrow_constructible<expect<throw_construct>, throw_construct&&>()));
      EXPECT_TRUE((std::is_nothrow_constructible<expect<throw_construct>, throw_construct&>()));
      EXPECT_TRUE((std::is_nothrow_constructible<expect<throw_construct>, throw_construct const&>()));
      EXPECT_TRUE(!(std::is_nothrow_constructible<expect<throw_construct>, expect<int>>()));
      EXPECT_TRUE(!(std::is_nothrow_constructible<expect<throw_construct>, expect<int>&&>()));
      EXPECT_TRUE(!(std::is_nothrow_constructible<expect<throw_construct>, expect<int>&>()));
      EXPECT_TRUE(!(std::is_nothrow_constructible<expect<throw_construct>, expect<int> const&>()));
      EXPECT_TRUE(std::is_nothrow_copy_constructible<expect<throw_construct>>());
      EXPECT_TRUE(std::is_nothrow_move_constructible<expect<throw_construct>>());
      EXPECT_TRUE(std::is_nothrow_copy_assignable<expect<throw_construct>>());
      EXPECT_TRUE(std::is_nothrow_move_assignable<expect<throw_construct>>());
      EXPECT_TRUE(std::is_nothrow_destructible<expect<throw_construct>>());
  
      EXPECT_TRUE((std::is_nothrow_constructible<expect<throw_copies>, std::error_code>()));
      EXPECT_TRUE((std::is_nothrow_constructible<expect<throw_copies>, std::error_code&&>()));
      EXPECT_TRUE((std::is_nothrow_constructible<expect<throw_copies>, std::error_code&>()));
      EXPECT_TRUE((std::is_nothrow_constructible<expect<throw_copies>, std::error_code const&>()));
      EXPECT_TRUE((std::is_nothrow_constructible<expect<throw_copies>, throw_copies>()));
      EXPECT_TRUE((std::is_nothrow_constructible<expect<throw_copies>, throw_copies&&>()));
      EXPECT_TRUE(!(std::is_nothrow_constructible<expect<throw_copies>, throw_copies&>()));
      EXPECT_TRUE(!(std::is_nothrow_constructible<expect<throw_copies>, throw_copies const&>()));
      EXPECT_TRUE(!std::is_nothrow_copy_constructible<expect<throw_copies>>());
      EXPECT_TRUE(std::is_nothrow_move_constructible<expect<throw_copies>>());
      EXPECT_TRUE(!std::is_nothrow_copy_assignable<expect<throw_copies>>());
      EXPECT_TRUE(std::is_nothrow_move_assignable<expect<throw_copies>>());
      EXPECT_TRUE(std::is_nothrow_destructible<expect<throw_copies>>());
      EXPECT_TRUE(noexcept(std::declval<expect<throw_copies>>().equal(std::declval<expect<throw_copies>>())));
      EXPECT_TRUE(noexcept(std::declval<expect<throw_copies>>().equal(std::declval<throw_copies>())));
      EXPECT_TRUE(noexcept(std::declval<expect<throw_copies>>() == std::declval<expect<throw_copies>>()));
      EXPECT_TRUE(noexcept(std::declval<expect<throw_copies>>() == std::declval<throw_copies>()));
      EXPECT_TRUE(noexcept(std::declval<throw_copies>() == std::declval<expect<throw_copies>>()));
      EXPECT_TRUE(noexcept(std::declval<expect<throw_copies>>() != std::declval<expect<throw_copies>>()));
      EXPECT_TRUE(noexcept(std::declval<expect<throw_copies>>() != std::declval<throw_copies>()));
      EXPECT_TRUE(noexcept(std::declval<throw_copies>() != std::declval<expect<throw_copies>>()));
      EXPECT_TRUE(noexcept(std::declval<expect<throw_copies>>().equal(std::declval<expect<throw_moves>>())));
      EXPECT_TRUE(noexcept(std::declval<expect<throw_copies>>().equal(std::declval<throw_moves>())));
      EXPECT_TRUE(noexcept(std::declval<expect<throw_copies>>() == std::declval<expect<throw_moves>>()));
      EXPECT_TRUE(noexcept(std::declval<expect<throw_copies>>() == std::declval<throw_moves>()));
      EXPECT_TRUE(noexcept(std::declval<throw_moves>() == std::declval<expect<throw_copies>>()));
      EXPECT_TRUE(noexcept(std::declval<expect<throw_copies>>() != std::declval<expect<throw_moves>>()));
      EXPECT_TRUE(noexcept(std::declval<expect<throw_copies>>() != std::declval<throw_moves>()));
      EXPECT_TRUE(noexcept(std::declval<throw_moves>() != std::declval<expect<throw_copies>>()));
  
      EXPECT_TRUE((std::is_nothrow_constructible<expect<throw_moves>, std::error_code>()));
      EXPECT_TRUE((std::is_nothrow_constructible<expect<throw_moves>, std::error_code&&>()));
      EXPECT_TRUE((std::is_nothrow_constructible<expect<throw_moves>, std::error_code&>()));
      EXPECT_TRUE((std::is_nothrow_constructible<expect<throw_moves>, std::error_code const&>()));
      EXPECT_TRUE(!(std::is_nothrow_constructible<expect<throw_moves>, throw_moves>()));
      EXPECT_TRUE(!(std::is_nothrow_constructible<expect<throw_moves>, throw_moves&&>()));
      EXPECT_TRUE(!(std::is_nothrow_constructible<expect<throw_moves>, throw_moves&>()));
      EXPECT_TRUE(!(std::is_nothrow_constructible<expect<throw_moves>, throw_moves const&>()));
      EXPECT_TRUE(std::is_nothrow_copy_constructible<expect<throw_moves>>());
      EXPECT_TRUE(!std::is_nothrow_move_constructible<expect<throw_moves>>());
      EXPECT_TRUE(std::is_nothrow_copy_assignable<expect<throw_moves>>());
      EXPECT_TRUE(!std::is_nothrow_move_assignable<expect<throw_moves>>());
      EXPECT_TRUE(std::is_nothrow_destructible<expect<throw_copies>>());
      EXPECT_TRUE(!noexcept(std::declval<expect<throw_moves>>().equal(std::declval<expect<throw_moves>>())));
      EXPECT_TRUE(!noexcept(std::declval<expect<throw_moves>>().equal(std::declval<throw_moves>())));
      EXPECT_TRUE(!noexcept(std::declval<expect<throw_moves>>() == std::declval<expect<throw_moves>>()));
      EXPECT_TRUE(!noexcept(std::declval<expect<throw_moves>>() == std::declval<throw_moves>()));
      EXPECT_TRUE(!noexcept(std::declval<throw_moves>() == std::declval<expect<throw_moves>>()));
      EXPECT_TRUE(!noexcept(std::declval<expect<throw_moves>>() != std::declval<expect<throw_moves>>()));
      EXPECT_TRUE(!noexcept(std::declval<expect<throw_moves>>() != std::declval<throw_moves>()));
      EXPECT_TRUE(!noexcept(std::declval<throw_moves>() != std::declval<expect<throw_moves>>()));
      EXPECT_TRUE(!noexcept(std::declval<expect<throw_moves>>().equal(std::declval<expect<throw_copies>>())));
      EXPECT_TRUE(!noexcept(std::declval<expect<throw_moves>>().equal(std::declval<throw_copies>())));
      EXPECT_TRUE(!noexcept(std::declval<expect<throw_moves>>() == std::declval<expect<throw_copies>>()));
      EXPECT_TRUE(!noexcept(std::declval<expect<throw_moves>>() == std::declval<throw_copies>()));
      EXPECT_TRUE(!noexcept(std::declval<throw_copies>() == std::declval<expect<throw_moves>>()));
      EXPECT_TRUE(!noexcept(std::declval<expect<throw_moves>>() != std::declval<expect<throw_copies>>()));
      EXPECT_TRUE(!noexcept(std::declval<expect<throw_moves>>() != std::declval<throw_copies>()));
      EXPECT_TRUE(!noexcept(std::declval<throw_copies>() != std::declval<expect<throw_moves>>()));
  }
  
  TEST(Expect, Trivial)
  {
      EXPECT_TRUE(std::is_trivially_copy_constructible<expect<void>>());
      EXPECT_TRUE(std::is_trivially_move_constructible<expect<void>>());
      EXPECT_TRUE(std::is_trivially_destructible<expect<void>>());
  }
  
  TEST(Expect, Assignment)
  { 
      expect<std::string> val1{std::string{}};
      expect<std::string> val2{"foobar"};
  
      ASSERT_TRUE(val1.has_value());
      ASSERT_TRUE(val2.has_value());
      EXPECT_TRUE(bool(val1));
      EXPECT_TRUE(bool(val2));
      EXPECT_TRUE(!val1.has_error());
      EXPECT_TRUE(!val2.has_error());
      EXPECT_EQ(val1.value(), std::string{});
      EXPECT_TRUE(*val1 == std::string{});
      EXPECT_TRUE(boost::equals(val1->c_str(), ""));
      EXPECT_TRUE(val2.value() == "foobar");
      EXPECT_TRUE(*val2 == "foobar");
      EXPECT_TRUE(boost::equals(val2->c_str(), "foobar"));
      EXPECT_EQ(val1.error(), std::error_code{});
      EXPECT_EQ(val2.error(), std::error_code{});
      EXPECT_TRUE(!val1.equal(std::error_code{}));
      EXPECT_TRUE(!val2.equal(std::error_code{}));
      EXPECT_TRUE(!(val1 == std::error_code{}));
      EXPECT_TRUE(!(std::error_code{} == val1));
      EXPECT_TRUE(!(val2 == std::error_code{}));
      EXPECT_TRUE(!(std::error_code{} == val2));
      EXPECT_TRUE(val1 != std::error_code{});
      EXPECT_TRUE(std::error_code{} != val1);
      EXPECT_TRUE(val2 != std::error_code{});
      EXPECT_TRUE(std::error_code{} != val2);
      EXPECT_TRUE(!val1.matches(std::error_condition{}));
      EXPECT_TRUE(!val2.matches(std::error_condition{}));
  
      val1 = std::move(val2);
  
      ASSERT_TRUE(val1.has_value());
      ASSERT_TRUE(val2.has_value());
      EXPECT_TRUE(bool(val1));
      EXPECT_TRUE(bool(val2));
      EXPECT_TRUE(!val1.has_error());
      EXPECT_TRUE(!val2.has_error());
      EXPECT_EQ(val1.value(), "foobar");
      EXPECT_TRUE(*val1 == "foobar");
      EXPECT_TRUE(boost::equals(val1->c_str(), "foobar"));
      EXPECT_EQ(val2.value(), std::string{});
      EXPECT_TRUE(*val2 == std::string{});
      EXPECT_TRUE(boost::equals(val2->c_str(), ""));
      EXPECT_EQ(val1.error(), std::error_code{});
      EXPECT_EQ(val2.error(), std::error_code{});
      EXPECT_TRUE(!val1.equal(std::error_code{}));
      EXPECT_TRUE(!val2.equal(std::error_code{}));
      EXPECT_TRUE(!(val1 == std::error_code{}));
      EXPECT_TRUE(!(std::error_code{} == val1));
      EXPECT_TRUE(!(val2 == std::error_code{}));
      EXPECT_TRUE(!(std::error_code{} == val2));
      EXPECT_TRUE(val1 != std::error_code{});
      EXPECT_TRUE(std::error_code{} != val1);
      EXPECT_TRUE(val2 != std::error_code{});
      EXPECT_TRUE(std::error_code{} != val2);
      EXPECT_TRUE(!val1.matches(std::error_condition{}));
      EXPECT_TRUE(!val2.matches(std::error_condition{}));
  
      val2 = val1;
  
      ASSERT_TRUE(val1.has_value());
      ASSERT_TRUE(val2.has_value());
      EXPECT_TRUE(bool(val1));
      EXPECT_TRUE(bool(val2));
      EXPECT_TRUE(!val1.has_error());
      EXPECT_TRUE(!val2.has_error());
      EXPECT_EQ(val1.value(), "foobar");
      EXPECT_TRUE(*val1 == "foobar");
      EXPECT_TRUE(boost::equals(val1->c_str(), "foobar"));
      EXPECT_EQ(val2.value(), "foobar");
      EXPECT_TRUE(*val2 == "foobar");
      EXPECT_TRUE(boost::equals(val2->c_str(), "foobar"));
      EXPECT_EQ(val1.error(), std::error_code{});
      EXPECT_EQ(val2.error(), std::error_code{});
      EXPECT_TRUE(!val1.equal(std::error_code{}));
      EXPECT_TRUE(!val2.equal(std::error_code{}));
      EXPECT_TRUE(!(val1 == std::error_code{}));
      EXPECT_TRUE(!(std::error_code{} == val1));
      EXPECT_TRUE(!(val2 == std::error_code{}));
      EXPECT_TRUE(!(std::error_code{} == val2));
      EXPECT_TRUE(val1 != std::error_code{});
      EXPECT_TRUE(std::error_code{} != val1);
      EXPECT_TRUE(val2 != std::error_code{});
      EXPECT_TRUE(std::error_code{} != val2);
      EXPECT_TRUE(!val1.matches(std::error_condition{}));
      EXPECT_TRUE(!val2.matches(std::error_condition{}));
  
      val1 = make_error_code(common_error::kInvalidArgument);
  
      ASSERT_TRUE(val1.has_error());
      ASSERT_TRUE(val2.has_value());
      EXPECT_TRUE(!val1);
      EXPECT_TRUE(bool(val2));
      EXPECT_TRUE(!val1.has_value());
      EXPECT_TRUE(!val2.has_error());
      EXPECT_EQ(val1.error(), common_error::kInvalidArgument);
      EXPECT_TRUE(val1 == common_error::kInvalidArgument);
      EXPECT_TRUE(common_error::kInvalidArgument == val1);
      EXPECT_STREQ(val2.value().c_str(), "foobar");
      EXPECT_TRUE(*val2 == "foobar");
      EXPECT_TRUE(boost::equals(val2->c_str(), "foobar"));
      EXPECT_NE(val1.error(), std::error_code{});
      EXPECT_EQ(val2.error(), std::error_code{});
      EXPECT_TRUE(val1.equal(common_error::kInvalidArgument));
      EXPECT_TRUE(!val2.equal(std::error_code{}));
      EXPECT_TRUE(!(val1 == std::error_code{}));
      EXPECT_TRUE(!(std::error_code{} == val1));
      EXPECT_TRUE(!(val2 == std::error_code{}));
      EXPECT_TRUE(!(std::error_code{} == val2));
      EXPECT_TRUE(val1 != std::error_code{});
      EXPECT_TRUE(std::error_code{} != val1);
      EXPECT_TRUE(val2 != std::error_code{});
      EXPECT_TRUE(std::error_code{} != val2);
      EXPECT_TRUE(val1.matches(std::errc::invalid_argument));
      EXPECT_TRUE(!val1.matches(std::error_condition{}));
      EXPECT_TRUE(!val2.matches(std::error_condition{}));
  
      val2 = val1;
  
      ASSERT_TRUE(val1.has_error());
      ASSERT_TRUE(val2.has_error());
      EXPECT_TRUE(!val1);
      EXPECT_TRUE(!val2);
      EXPECT_TRUE(!val1.has_value());
      EXPECT_TRUE(!val2.has_value());
      EXPECT_EQ(val1.error(), common_error::kInvalidArgument);
      EXPECT_TRUE(val1 == common_error::kInvalidArgument);
      EXPECT_TRUE(common_error::kInvalidArgument == val1);
      EXPECT_EQ(val2.error(), common_error::kInvalidArgument);
      EXPECT_TRUE(val2 == common_error::kInvalidArgument);
      EXPECT_TRUE(common_error::kInvalidArgument == val2);
      EXPECT_NE(val1.error(), std::error_code{});
      EXPECT_NE(val2.error(), std::error_code{});
      EXPECT_TRUE(val1.equal(common_error::kInvalidArgument));
      EXPECT_TRUE(val2.equal(common_error::kInvalidArgument));
      EXPECT_TRUE(!(val1 == std::error_code{}));
      EXPECT_TRUE(!(std::error_code{} == val1));
      EXPECT_TRUE(!(val2 == std::error_code{}));
      EXPECT_TRUE(!(std::error_code{} == val2));
      EXPECT_TRUE(val1 != std::error_code{});
      EXPECT_TRUE(std::error_code{} != val1);
      EXPECT_TRUE(val2 != std::error_code{});
      EXPECT_TRUE(std::error_code{} != val2);
      EXPECT_TRUE(val1.matches(std::errc::invalid_argument));
      EXPECT_TRUE(val2.matches(std::errc::invalid_argument));
      EXPECT_TRUE(!val1.matches(std::error_condition{}));
      EXPECT_TRUE(!val2.matches(std::error_condition{}));
  
      val1 = std::string{"barfoo"};
  
      ASSERT_TRUE(val1.has_value());
      ASSERT_TRUE(val2.has_error());
      EXPECT_TRUE(bool(val1));
      EXPECT_TRUE(!val2);
      EXPECT_TRUE(!val1.has_error());
      EXPECT_TRUE(!val2.has_value());
      EXPECT_STREQ(val1.value().c_str(), "barfoo");
      EXPECT_TRUE(*val1 == "barfoo");
      EXPECT_TRUE(boost::equals(val1->c_str(), "barfoo"));
      EXPECT_EQ(val2.error(), common_error::kInvalidArgument);
      EXPECT_TRUE(val2 == common_error::kInvalidArgument);
      EXPECT_TRUE(common_error::kInvalidArgument == val2);
      EXPECT_EQ(val1.error(), std::error_code{});
      EXPECT_NE(val2.error(), std::error_code{});
      EXPECT_TRUE(!val1.equal(std::error_code{}));
      EXPECT_TRUE(val2.equal(common_error::kInvalidArgument));
      EXPECT_TRUE(!(val1 == std::error_code{}));
      EXPECT_TRUE(!(std::error_code{} == val1));
      EXPECT_TRUE(!(val2 == std::error_code{}));
      EXPECT_TRUE(!(std::error_code{} == val2));
      EXPECT_TRUE(val1 != std::error_code{});
      EXPECT_TRUE(std::error_code{} != val1);
      EXPECT_TRUE(val2 != std::error_code{});
      EXPECT_TRUE(std::error_code{} != val2);
      EXPECT_TRUE(val2.matches(std::errc::invalid_argument));
      EXPECT_TRUE(!val1.matches(std::error_condition{}));
      EXPECT_TRUE(!val2.matches(std::error_condition{}));
  
      val2 = val1;
  
      ASSERT_TRUE(val1.has_value());
      ASSERT_TRUE(val2.has_value());
      EXPECT_TRUE(bool(val1));
      EXPECT_TRUE(bool(val2));
      EXPECT_TRUE(!val1.has_error());
      EXPECT_TRUE(!val2.has_error());
      EXPECT_EQ(val1.value(), "barfoo");
      EXPECT_TRUE(*val1 == "barfoo");
      EXPECT_TRUE(boost::equals(val1->c_str(), "barfoo"));
      EXPECT_EQ(val2.value(), "barfoo");
      EXPECT_TRUE(*val2 == "barfoo");
      EXPECT_TRUE(boost::equals(val2->c_str(), "barfoo"));
      EXPECT_EQ(val1.error(), std::error_code{});
      EXPECT_EQ(val2.error(), std::error_code{});
      EXPECT_TRUE(!val1.equal(std::error_code{}));
      EXPECT_TRUE(!val2.equal(std::error_code{}));
      EXPECT_TRUE(!(val1 == std::error_code{}));
      EXPECT_TRUE(!(std::error_code{} == val1));
      EXPECT_TRUE(!(val2 == std::error_code{}));
      EXPECT_TRUE(!(std::error_code{} == val2));
      EXPECT_TRUE(val1 != std::error_code{});
      EXPECT_TRUE(std::error_code{} != val1);
      EXPECT_TRUE(val2 != std::error_code{});
      EXPECT_TRUE(std::error_code{} != val2);
      EXPECT_TRUE(!val1.matches(std::error_condition{}));
      EXPECT_TRUE(!val2.matches(std::error_condition{}));
  }
  
  TEST(Expect, AssignmentThrowsOnMove)
  {
      struct construct_error {};
      struct assignment_error {};
  
      struct throw_on_move {
          std::string msg;
  
          throw_on_move(const char* msg) : msg(msg) {}
          throw_on_move(throw_on_move&&) {
              throw construct_error{};
          }
          throw_on_move(throw_on_move const&) = default;
          ~throw_on_move() = default;
          throw_on_move& operator=(throw_on_move&&) {
              throw assignment_error{};
          }
          throw_on_move& operator=(throw_on_move const&) = default;
      };
  
      expect<throw_on_move> val1{expect<const char*>{"foobar"}};
      expect<throw_on_move> val2{common_error::kInvalidArgument};
  
      ASSERT_TRUE(val1.has_value());
      ASSERT_TRUE(val2.has_error());
      EXPECT_TRUE(!val1.has_error());
      EXPECT_TRUE(!val2.has_value());
      EXPECT_STREQ(val1->msg.c_str(), "foobar");
      EXPECT_EQ(val2.error(), common_error::kInvalidArgument);
  
      EXPECT_THROW(val2 = std::move(val1), construct_error);
  
      ASSERT_TRUE(val1.has_value());
      ASSERT_TRUE(val2.has_error());
      EXPECT_TRUE(!val1.has_error());
      EXPECT_TRUE(!val2.has_value());
      EXPECT_STREQ(val1->msg.c_str(), "foobar");
      EXPECT_EQ(val2.error(), common_error::kInvalidArgument);
  
      EXPECT_THROW(val1 = expect<const char*>{"barfoo"}, assignment_error);
  
      ASSERT_TRUE(val1.has_value());
      ASSERT_TRUE(val2.has_error());
      EXPECT_TRUE(!val1.has_error());
      EXPECT_TRUE(!val2.has_value());
      EXPECT_STREQ(val1->msg.c_str(), "foobar");
      EXPECT_EQ(val2.error(), common_error::kInvalidArgument);
  
      EXPECT_NO_THROW(val2 = val1);
  
      ASSERT_TRUE(val1.has_value());
      ASSERT_TRUE(val2.has_value());
      EXPECT_TRUE(!val1.has_error());
      EXPECT_TRUE(!val2.has_error());
      EXPECT_STREQ(val1->msg.c_str(), "foobar");
      EXPECT_STREQ(val2->msg.c_str(), "foobar");
  }
  
  TEST(Expect, EqualWithStrings)
  {
      expect<std::string> val1{std::string{}};
      expect<std::string> val2{"barfoo"};
      expect<boost::string_ref> val3{boost::string_ref{}};
  
      EXPECT_TRUE(!val1.equal(val2));
      EXPECT_TRUE(val1.equal(val3));
      EXPECT_TRUE(!val2.equal(val1));
      EXPECT_TRUE(!val2.equal(val3));
      EXPECT_TRUE(val3.equal(val1));
      EXPECT_TRUE(!val3.equal(val2));
      EXPECT_TRUE(!(val1 == val2));
      EXPECT_TRUE(!(val2 == val1));
      EXPECT_TRUE(val1 == val3);
      EXPECT_TRUE(val3 == val1);
      EXPECT_TRUE(!(val2 == val3));
      EXPECT_TRUE(!(val3 == val2));
      EXPECT_TRUE(val1 != val2);
      EXPECT_TRUE(val2 != val1);
      EXPECT_TRUE(!(val1 != val3));
      EXPECT_TRUE(!(val3 != val1));
      EXPECT_TRUE(val2 != val3);
      EXPECT_TRUE(val3 != val2);
  
      EXPECT_TRUE(val1.equal(""));
      EXPECT_TRUE(val2.equal("barfoo"));
      EXPECT_TRUE(val3.equal(""));
      EXPECT_TRUE(!val1.equal(std::error_code{}));
      EXPECT_TRUE(!val2.equal(std::error_code{}));
      EXPECT_TRUE(!val3.equal(std::error_code{}));
      EXPECT_TRUE(val1 == "");
      EXPECT_TRUE("" == val1);
      EXPECT_TRUE(val2 == "barfoo");
      EXPECT_TRUE("barfoo" == val2);
      EXPECT_TRUE(val3 == "");
      EXPECT_TRUE("" == val3);
      EXPECT_TRUE(!(val1 != ""));
      EXPECT_TRUE(!("" != val1));
      EXPECT_TRUE(!(val2 != "barfoo"));
      EXPECT_TRUE(!("barfoo" != val2));
      EXPECT_TRUE(!(val3 != ""));
      EXPECT_TRUE(!("" != val3));
      EXPECT_TRUE(!(val1 == std::error_code{}));
      EXPECT_TRUE(!(std::error_code{} == val1));
      EXPECT_TRUE(!(val2 == std::error_code{}));
      EXPECT_TRUE(!(std::error_code{} == val2));
      EXPECT_TRUE(!(val3 == std::error_code{}));
      EXPECT_TRUE(!(std::error_code{} == val3));
      EXPECT_TRUE(val1 != std::error_code{});
      EXPECT_TRUE(std::error_code{} != val1);
      EXPECT_TRUE(val2 != std::error_code{});
      EXPECT_TRUE(std::error_code{} != val2);
      EXPECT_TRUE(val3 != std::error_code{});
      EXPECT_TRUE(std::error_code{} != val3);
      EXPECT_TRUE(!val1.matches(std::error_condition{}));
      EXPECT_TRUE(!val2.matches(std::error_condition{}));
      EXPECT_TRUE(!val3.matches(std::error_condition{}));
  
      val2 = make_error_code(common_error::kInvalidArgument);
  
      EXPECT_TRUE(!val1.equal(val2));
      EXPECT_TRUE(val1.equal(val3));
      EXPECT_TRUE(!val2.equal(val1));
      EXPECT_TRUE(!val2.equal(val3));
      EXPECT_TRUE(val3.equal(val1));
      EXPECT_TRUE(!val3.equal(val2));
      EXPECT_TRUE(!(val1 == val2));
      EXPECT_TRUE(!(val2 == val1));
      EXPECT_TRUE(val1 == val3);
      EXPECT_TRUE(val3 == val1);
      EXPECT_TRUE(!(val2 == val3));
      EXPECT_TRUE(!(val3 == val2));
      EXPECT_TRUE(val1 != val2);
      EXPECT_TRUE(val2 != val1);
      EXPECT_TRUE(!(val1 != val3));
      EXPECT_TRUE(!(val3 != val1));
      EXPECT_TRUE(val2 != val3);
      EXPECT_TRUE(val3 != val2);
  
      EXPECT_TRUE(!val1.equal(common_error::kInvalidArgument));
      EXPECT_TRUE(val2.equal(common_error::kInvalidArgument));
      EXPECT_TRUE(!val3.equal(common_error::kInvalidArgument));
      EXPECT_TRUE(val2 == common_error::kInvalidArgument);
      EXPECT_TRUE(common_error::kInvalidArgument == val2);
      EXPECT_TRUE(!(val2 != common_error::kInvalidArgument));
      EXPECT_TRUE(!(common_error::kInvalidArgument != val2));
      EXPECT_TRUE(val2.matches(std::errc::invalid_argument));
      EXPECT_TRUE(!val2.matches(std::error_condition{}));
  
      val1 = expect<std::string>{"barfoo"};
  
      EXPECT_TRUE(!val1.equal(val2));
      EXPECT_TRUE(!val1.equal(val3));
      EXPECT_TRUE(!val2.equal(val1));
      EXPECT_TRUE(!val2.equal(val3));
      EXPECT_TRUE(!val3.equal(val1));
      EXPECT_TRUE(!val3.equal(val2));
      EXPECT_TRUE(!(val1 == val2));
      EXPECT_TRUE(!(val2 == val1));
      EXPECT_TRUE(!(val1 == val3));
      EXPECT_TRUE(!(val3 == val1));
      EXPECT_TRUE(!(val2 == val3));
      EXPECT_TRUE(!(val3 == val2));
      EXPECT_TRUE(val1 != val2);
      EXPECT_TRUE(val2 != val1);
      EXPECT_TRUE(val1 != val3);
      EXPECT_TRUE(val3 != val1);
      EXPECT_TRUE(val2 != val3);
      EXPECT_TRUE(val3 != val2);
  
      EXPECT_TRUE(val1.equal("barfoo"));
      EXPECT_TRUE(val1 == "barfoo");
      EXPECT_TRUE("barfoo" == val1);
      EXPECT_TRUE(!(val1 != "barfoo"));
      EXPECT_TRUE(!("barfoo" != val1));
      EXPECT_TRUE(!val1.equal(common_error::kInvalidArgument));
      EXPECT_TRUE(!(val1 == common_error::kInvalidArgument));
      EXPECT_TRUE(!(common_error::kInvalidArgument == val1));
      EXPECT_TRUE(!(val1 == std::error_code{}));
      EXPECT_TRUE(!(std::error_code{} == val1));
      EXPECT_TRUE(!val1.matches(std::error_condition{}));
      EXPECT_TRUE(!val1.matches(std::errc::invalid_argument));
  }
  
  TEST(Expect, EqualWithVoid)
  {
      const expect<void> val1;
      expect<void> val2;
  
      EXPECT_TRUE(val1.equal(val2));
      EXPECT_TRUE(val2.equal(val1));
      EXPECT_TRUE(!val1.equal(std::error_code{}));
      EXPECT_TRUE(!val2.equal(std::error_code{}));
      EXPECT_TRUE(val1 == val2);
      EXPECT_TRUE(val2 == val1);
      EXPECT_TRUE(!(val1 == std::error_code{}));
      EXPECT_TRUE(!(std::error_code{} == val1));
      EXPECT_TRUE(!(val2 == std::error_code{}));
      EXPECT_TRUE(!(std::error_code{} == val2));
      EXPECT_TRUE(!(val1 != val2));
      EXPECT_TRUE(!(val2 != val1));
      EXPECT_TRUE(val1 != std::error_code{});
      EXPECT_TRUE(std::error_code{} != val1);
      EXPECT_TRUE(!(val2 == std::error_code{}));
      EXPECT_TRUE(!(std::error_code{} == val2));
  
      val2 = make_error_code(common_error::kInvalidArgument);
  
      EXPECT_TRUE(!val1.equal(val2));
      EXPECT_TRUE(!val2.equal(val1));
      EXPECT_TRUE(!val1.equal(common_error::kInvalidArgument));
      EXPECT_TRUE(val2.equal(common_error::kInvalidArgument));
      EXPECT_TRUE(!val2.equal(std::error_code{}));
      EXPECT_TRUE(!(val1 == val2));
      EXPECT_TRUE(!(val2 == val1));
      EXPECT_TRUE(val2 == common_error::kInvalidArgument);
      EXPECT_TRUE(common_error::kInvalidArgument == val2);
      EXPECT_TRUE(!(val2 == std::error_code{}));
      EXPECT_TRUE(!(std::error_code{} == val2));
      EXPECT_TRUE(val1 != val2);
      EXPECT_TRUE(val2 != val1);
      EXPECT_TRUE(!(val2 != common_error::kInvalidArgument));
      EXPECT_TRUE(!(common_error::kInvalidArgument != val2));
      EXPECT_TRUE(val2 != std::error_code{});
      EXPECT_TRUE(std::error_code{} != val2);
  }
  
  TEST(Expect, EqualNoCopies)
  {
      struct copy_error {};
  
      struct throw_on_copy {
          throw_on_copy() = default;
          throw_on_copy(int) noexcept {}
          throw_on_copy(throw_on_copy const&) {
              throw copy_error{};
          }
          ~throw_on_copy() = default;
          throw_on_copy& operator=(throw_on_copy const&) {
              throw copy_error{};
          }
  
          bool operator==(throw_on_copy const&) const noexcept { return true; }
      };
  
      expect<throw_on_copy> val1{expect<int>{0}};
      expect<throw_on_copy> val2{expect<int>{0}};
  
      EXPECT_TRUE(val1.equal(val2));
      EXPECT_TRUE(val2.equal(val1));
      EXPECT_TRUE(val1 == val2);
      EXPECT_TRUE(val2 == val1);
      EXPECT_TRUE(!(val1 != val2));
      EXPECT_TRUE(!(val2 != val1));
  
      EXPECT_TRUE(val1.equal(throw_on_copy{}));
      EXPECT_TRUE(val1 == throw_on_copy{});
      EXPECT_TRUE(throw_on_copy{} == val1);
      EXPECT_TRUE(!(val1 != throw_on_copy{}));
      EXPECT_TRUE(!(throw_on_copy{} != val1));
  
      throw_on_copy val3;
  
      EXPECT_TRUE(val1.equal(val3));
      EXPECT_TRUE(val1 == val3);
      EXPECT_TRUE(val3 == val1);
      EXPECT_TRUE(!(val1 != val3));
      EXPECT_TRUE(!(val3 != val1));
  
      expect<throw_on_copy> val4{common_error::kInvalidArgument};
  
      EXPECT_TRUE(!val4.equal(throw_on_copy{}));
      EXPECT_TRUE(!(val4 == throw_on_copy{}));
      EXPECT_TRUE(!(throw_on_copy{} == val4));
      EXPECT_TRUE(val4 != throw_on_copy{});
      EXPECT_TRUE(throw_on_copy{} != val4);
      EXPECT_TRUE(!val4.equal(val3));
      EXPECT_TRUE(!(val4 == val3));
      EXPECT_TRUE(!(val3 == val4));
      EXPECT_TRUE(val4 != val3);
      EXPECT_TRUE(val3 != val4);
  }
  
  TEST(Expect, Macros) {
      EXPECT_TRUE(
          [] () -> ::common_error {
              jyocoin_PRECOND(true);
              return {common_error::kInvalidErrorCode};
          } () == common_error::kInvalidErrorCode
      );
      EXPECT_TRUE(
          [] () -> ::common_error {
              jyocoin_PRECOND(false);
              return {common_error::kInvalidErrorCode};
          } () == common_error::kInvalidArgument
      );
      EXPECT_TRUE(
          [] () -> std::error_code {
              jyocoin_PRECOND(true);
              return {common_error::kInvalidErrorCode};
          } () == common_error::kInvalidErrorCode
      );
      EXPECT_TRUE(
          [] () -> std::error_code {
              jyocoin_PRECOND(false);
              return {common_error::kInvalidErrorCode};
          } () == common_error::kInvalidArgument
      );
      EXPECT_TRUE(
          [] () -> expect<void> {
              jyocoin_PRECOND(true);
              return {common_error::kInvalidErrorCode};
          } () == common_error::kInvalidErrorCode
      );
      EXPECT_TRUE(
          [] () -> expect<void> {
              jyocoin_PRECOND(false);
              return {common_error::kInvalidErrorCode};
          } () == common_error::kInvalidArgument
      );
      EXPECT_TRUE(
          [] () -> expect<int> {
              jyocoin_PRECOND(true);
              return {common_error::kInvalidErrorCode};
          } () == common_error::kInvalidErrorCode
      );
      EXPECT_TRUE(
          [] () -> expect<int> {
              jyocoin_PRECOND(false);
              return {common_error::kInvalidErrorCode};
          } () == common_error::kInvalidArgument
      );
  
      EXPECT_TRUE(
          [] () -> std::error_code {
              jyocoin_CHECK(expect<void>{});
              return {common_error::kInvalidErrorCode};
          } () == common_error::kInvalidErrorCode
      );
      EXPECT_TRUE(
          [] () -> std::error_code {
              jyocoin_CHECK(expect<void>{common_error::kInvalidArgument});
              return {common_error::kInvalidErrorCode};
          } () == common_error::kInvalidArgument
      );
      EXPECT_TRUE(
          [] () -> expect<void> {
              jyocoin_CHECK(expect<void>{});
              return {common_error::kInvalidErrorCode};
          } () == common_error::kInvalidErrorCode
      );
      EXPECT_TRUE(
          [] () -> expect<void> {
              jyocoin_CHECK(expect<void>{common_error::kInvalidArgument});
              return {common_error::kInvalidErrorCode};
          } () == common_error::kInvalidArgument
      );
      EXPECT_TRUE(
          [] () -> expect<int> {
              jyocoin_CHECK(expect<void>{});
              return {common_error::kInvalidErrorCode};
          } () == common_error::kInvalidErrorCode
      );
      EXPECT_TRUE(
          [] () -> expect<int> {
              jyocoin_CHECK(expect<void>{common_error::kInvalidArgument});
              return {common_error::kInvalidErrorCode};
          } () == common_error::kInvalidArgument
      );
  
      EXPECT_NO_THROW(jyocoin_UNWRAP(success()));
      EXPECT_NO_THROW(jyocoin_UNWRAP(expect<void>{}));
      EXPECT_NO_THROW(jyocoin_UNWRAP(expect<int>{0}));
      EXPECT_THROW(
          jyocoin_UNWRAP(expect<void>{common_error::kInvalidArgument}), std::system_error
      );
      EXPECT_THROW(
          jyocoin_UNWRAP(expect<int>{common_error::kInvalidArgument}), std::system_error
      );
  }
  
  