M5Utility/test/expected/assignment.cpp

#include <gtest/gtest.h>
#include <m5_utility/stl/expected.hpp>

TEST(Expected, Assignment)
{
    m5::stl::expected<int, int> e1 = 42;
    m5::stl::expected<int, int> e2 = 17;
    m5::stl::expected<int, int> e3 = 21;
    m5::stl::expected<int, int> e4 = m5::stl::make_unexpected(42);
    m5::stl::expected<int, int> e5 = m5::stl::make_unexpected(17);
    m5::stl::expected<int, int> e6 = m5::stl::make_unexpected(21);

    e1 = e2;
    EXPECT_TRUE(e1);
    EXPECT_TRUE(*e1 == 17);
    EXPECT_TRUE(e2);
    EXPECT_TRUE(*e2 == 17);

    e1 = std::move(e2);
    EXPECT_TRUE(e1);
    EXPECT_TRUE(*e1 == 17);
    EXPECT_TRUE(e2);
    EXPECT_TRUE(*e2 == 17);

    e1 = 42;
    EXPECT_TRUE(e1);
    EXPECT_TRUE(*e1 == 42);

    auto unex = m5::stl::make_unexpected(12);
    e1        = unex;
    EXPECT_TRUE(!e1);
    EXPECT_TRUE(e1.error() == 12);

    e1 = m5::stl::make_unexpected(42);
    EXPECT_TRUE(!e1);
    EXPECT_TRUE(e1.error() == 42);

    e1 = e3;
    EXPECT_TRUE(e1);
    EXPECT_TRUE(*e1 == 21);

    e4 = e5;
    EXPECT_TRUE(!e4);
    EXPECT_TRUE(e4.error() == 17);

    e4 = std::move(e6);
    EXPECT_TRUE(!e4);
    EXPECT_TRUE(e4.error() == 21);

    e4 = e1;
    EXPECT_TRUE(e4);
    EXPECT_TRUE(*e4 == 21);
}

TEST(Expected, AssignmentDeletion)
{
    struct has_all {
        has_all() = default;

        has_all(const has_all &) = default;

        has_all(has_all &&) noexcept = default;

        has_all &operator=(const has_all &) = default;
    };

    m5::stl::expected<has_all, has_all> e1 = {};
    m5::stl::expected<has_all, has_all> e2 = {};
    e1                                     = e2;

    struct except_move {
        except_move() = default;

        except_move(const except_move &) = default;

        except_move(except_move &&) noexcept(false)
        {
        }

        except_move &operator=(const except_move &) = default;
    };

    // m5::stl::expected<except_move, except_move> e3 = {};
    // m5::stl::expected<except_move, except_move> e4 = {};
    // e3 = e4; //should not compile
}