/*******************************************************************************
 * This file is part of the "https://github.com/blackmatov/flat.hpp"
 * For conditions of distribution and use, see copyright notice in LICENSE.md
 * Copyright (C) 2019-2023, by Matvey Cherevko (blackmatov@gmail.com)
 ******************************************************************************/

#include <flat.hpp/flat_multiset.hpp>
#include "flat_tests.hpp"

#include <deque>
#include <string>
#include <string_view>

namespace
{
    using namespace flat_hpp;

    template < typename T >
    class dummy_less {
    public:
        dummy_less() = default;
        dummy_less(int ni) noexcept : i(ni) {}
        bool operator()(const T& l, const T& r) const {
            return l < r;
        }
        int i = 0;
    };

    template < typename T >
    class dummy_less2 {
        dummy_less2() = default;
        dummy_less2(dummy_less2&&) noexcept(false) {}
        bool operator()(const T& l, const T& r) const {
            return l < r;
        }
    };

    template < typename T >
    [[maybe_unused]] void swap(dummy_less2<T>&, dummy_less2<T>&) noexcept {
    }

    template < typename T >
    class dummy_less3 {
        dummy_less3() = default;
        dummy_less3(dummy_less3&&) noexcept(false) {}
        bool operator()(const T& l, const T& r) const {
            return l < r;
        }
    };

    template < typename T >
    constexpr std::add_const_t<T>& my_as_const(T& t) noexcept {
        return t;
    }
}

TEST_CASE("flat_multiset") {
    SUBCASE("guides") {
        {
            std::vector<int> vs;

            auto s0 = flat_multiset(vs.begin(), vs.end());
            auto s1 = flat_multiset(flat_hpp::sorted_range, vs.begin(), vs.end());
            auto s2 = flat_multiset(flat_hpp::sorted_unique_range, vs.begin(), vs.end());

            auto s3 = flat_multiset(vs.begin(), vs.end(), std::less<int>());
            auto s4 = flat_multiset(flat_hpp::sorted_range, vs.begin(), vs.end(), std::less<int>());
            auto s5 = flat_multiset(flat_hpp::sorted_unique_range, vs.begin(), vs.end(), std::less<int>());

            auto s6 = flat_multiset(vs.begin(), vs.end(), std::allocator<int>());
            auto s7 = flat_multiset(flat_hpp::sorted_range, vs.begin(), vs.end(), std::allocator<int>());
            auto s8 = flat_multiset(flat_hpp::sorted_unique_range, vs.begin(), vs.end(), std::allocator<int>());

            auto s9 = flat_multiset(vs.begin(), vs.end(), std::less<int>(), std::allocator<int>());
            auto s10 = flat_multiset(flat_hpp::sorted_range, vs.begin(), vs.end(), std::less<int>(), std::allocator<int>());
            auto s11 = flat_multiset(flat_hpp::sorted_unique_range, vs.begin(), vs.end(), std::less<int>(), std::allocator<int>());

            STATIC_REQUIRE(std::is_same_v<decltype(s0)::key_type, int>);
            STATIC_REQUIRE(std::is_same_v<decltype(s1)::key_type, int>);
            STATIC_REQUIRE(std::is_same_v<decltype(s2)::key_type, int>);
            STATIC_REQUIRE(std::is_same_v<decltype(s3)::key_type, int>);
            STATIC_REQUIRE(std::is_same_v<decltype(s4)::key_type, int>);
            STATIC_REQUIRE(std::is_same_v<decltype(s5)::key_type, int>);
            STATIC_REQUIRE(std::is_same_v<decltype(s6)::key_type, int>);
            STATIC_REQUIRE(std::is_same_v<decltype(s7)::key_type, int>);
            STATIC_REQUIRE(std::is_same_v<decltype(s8)::key_type, int>);
            STATIC_REQUIRE(std::is_same_v<decltype(s9)::key_type, int>);
            STATIC_REQUIRE(std::is_same_v<decltype(s10)::key_type, int>);
            STATIC_REQUIRE(std::is_same_v<decltype(s11)::key_type, int>);
        }

        {
            auto s1 = flat_multiset({1, 2});
            auto s2 = flat_multiset(flat_hpp::sorted_range, {1, 2});
            auto s3 = flat_multiset(flat_hpp::sorted_unique_range, {1, 2});

            STATIC_REQUIRE(std::is_same_v<decltype(s1)::key_type, int>);
            STATIC_REQUIRE(std::is_same_v<decltype(s2)::key_type, int>);
            STATIC_REQUIRE(std::is_same_v<decltype(s3)::key_type, int>);
        }

        {
            auto s1 = flat_multiset({1, 2}, std::less<int>());
            auto s2 = flat_multiset(flat_hpp::sorted_range, {1, 2}, std::less<int>());
            auto s3 = flat_multiset(flat_hpp::sorted_unique_range, {1, 2}, std::less<int>());

            STATIC_REQUIRE(std::is_same_v<decltype(s1)::key_type, int>);
            STATIC_REQUIRE(std::is_same_v<decltype(s2)::key_type, int>);
            STATIC_REQUIRE(std::is_same_v<decltype(s3)::key_type, int>);
        }

        {
            auto s1 = flat_multiset({1, 2}, std::allocator<int>());
            auto s2 = flat_multiset(flat_hpp::sorted_range, {1, 2}, std::allocator<int>());
            auto s3 = flat_multiset(flat_hpp::sorted_unique_range, {1, 2}, std::allocator<int>());

            STATIC_REQUIRE(std::is_same_v<decltype(s1)::key_type, int>);
            STATIC_REQUIRE(std::is_same_v<decltype(s2)::key_type, int>);
            STATIC_REQUIRE(std::is_same_v<decltype(s3)::key_type, int>);
        }

        {
            auto s1 = flat_multiset({1, 2}, std::less<int>(), std::allocator<int>());
            auto s2 = flat_multiset(flat_hpp::sorted_range, {1, 2}, std::less<int>(), std::allocator<int>());
            auto s3 = flat_multiset(flat_hpp::sorted_unique_range, {1, 2}, std::less<int>(), std::allocator<int>());

            STATIC_REQUIRE(std::is_same_v<decltype(s1)::key_type, int>);
            STATIC_REQUIRE(std::is_same_v<decltype(s2)::key_type, int>);
            STATIC_REQUIRE(std::is_same_v<decltype(s3)::key_type, int>);
        }
    }
    SUBCASE("detail") {
        STATIC_REQUIRE(detail::is_transparent<std::less<>, int>::value);
        STATIC_REQUIRE_FALSE(detail::is_transparent<std::less<int>, int>::value);
    }
    SUBCASE("sizeof") {
        REQUIRE(sizeof(flat_multiset<int>) == sizeof(std::vector<int>));

        struct vc : flat_multiset<int>::value_compare {
            int i;
        };
        REQUIRE(sizeof(vc) == sizeof(int));
    }
    SUBCASE("noexcept") {
        using alloc_t = std::allocator<int>;
        using set_t = flat_multiset<int, dummy_less<int>, std::vector<int, alloc_t>>;
        using set2_t = flat_multiset<int, dummy_less2<int>>;
        using set3_t = flat_multiset<int, dummy_less3<int>>;

        STATIC_REQUIRE(std::is_nothrow_default_constructible_v<set_t>);
        STATIC_REQUIRE(std::is_nothrow_move_constructible_v<set_t>);
        STATIC_REQUIRE(std::is_nothrow_move_assignable_v<set_t>);
        STATIC_REQUIRE(std::is_nothrow_swappable_v<set_t>);
        STATIC_REQUIRE(std::is_nothrow_swappable_v<set2_t>);
        STATIC_REQUIRE(!std::is_nothrow_swappable_v<set3_t>);

        STATIC_REQUIRE(noexcept(std::declval<set_t&>().begin()));
        STATIC_REQUIRE(noexcept(std::declval<const set_t&>().begin()));
        STATIC_REQUIRE(noexcept(std::declval<const set_t&>().cbegin()));
        STATIC_REQUIRE(noexcept(std::declval<set_t&>().end()));
        STATIC_REQUIRE(noexcept(std::declval<const set_t&>().end()));
        STATIC_REQUIRE(noexcept(std::declval<const set_t&>().cend()));

        STATIC_REQUIRE(noexcept(std::declval<set_t&>().rbegin()));
        STATIC_REQUIRE(noexcept(std::declval<const set_t&>().rbegin()));
        STATIC_REQUIRE(noexcept(std::declval<const set_t&>().crbegin()));
        STATIC_REQUIRE(noexcept(std::declval<set_t&>().rend()));
        STATIC_REQUIRE(noexcept(std::declval<const set_t&>().rend()));
        STATIC_REQUIRE(noexcept(std::declval<const set_t&>().crend()));

        STATIC_REQUIRE(noexcept(std::declval<const set_t&>().empty()));
        STATIC_REQUIRE(noexcept(std::declval<const set_t&>().size()));
        STATIC_REQUIRE(noexcept(std::declval<const set_t&>().max_size()));
        STATIC_REQUIRE(noexcept(std::declval<const set_t&>().capacity()));

        STATIC_REQUIRE(noexcept(std::declval<set_t&>().clear()));
    }
    SUBCASE("types") {
        using set_t = flat_multiset<int>;

        STATIC_REQUIRE(std::is_same_v<set_t::key_type, int>);
        STATIC_REQUIRE(std::is_same_v<set_t::value_type, int>);

        STATIC_REQUIRE(std::is_same_v<set_t::size_type, std::size_t>);
        STATIC_REQUIRE(std::is_same_v<set_t::difference_type, std::ptrdiff_t>);

        STATIC_REQUIRE(std::is_same_v<set_t::reference, int&>);
        STATIC_REQUIRE(std::is_same_v<set_t::const_reference, const int&>);

        STATIC_REQUIRE(std::is_same_v<set_t::pointer, int*>);
        STATIC_REQUIRE(std::is_same_v<set_t::const_pointer, const int*>);
    }
    SUBCASE("ctors") {
        using alloc_t = std::allocator<int>;
        using set_t = flat_multiset<int, std::less<int>, std::vector<int, alloc_t>>;
        using set2_t = flat_multiset<int, std::greater<int>, std::vector<int, alloc_t>>;
        using vec_t = std::vector<int>;

        {
            auto s0 = set_t();
            auto s1 = set2_t(alloc_t());
            auto s2 = set_t(std::less<int>());
            auto s3 = set2_t(std::greater<int>(), alloc_t());
        }

        {
            vec_t v{1,2,3};
            auto s0 = set_t(v.cbegin(), v.cend());
            auto s1 = set2_t(v.cbegin(), v.cend(), alloc_t());
            auto s2 = set_t(v.cbegin(), v.cend(), std::less<int>());
            auto s3 = set2_t(v.cbegin(), v.cend(), std::greater<int>(), alloc_t());

            REQUIRE(vec_t(s0.begin(), s0.end()) == vec_t({1,2,3}));
            REQUIRE(vec_t(s1.begin(), s1.end()) == vec_t({3,2,1}));
            REQUIRE(vec_t(s2.begin(), s2.end()) == vec_t({1,2,3}));
            REQUIRE(vec_t(s3.begin(), s3.end()) == vec_t({3,2,1}));
        }

        {
            auto s0 = set_t({0,1,2});
            auto s1 = set2_t({0,1,2}, alloc_t());
            auto s2 = set_t({0,1,2}, std::less<int>());
            auto s3 = set2_t({0,1,2}, std::greater<int>(), alloc_t());

            REQUIRE(vec_t(s0.begin(), s0.end()) == vec_t({0,1,2}));
            REQUIRE(vec_t(s1.begin(), s1.end()) == vec_t({2,1,0}));
            REQUIRE(vec_t(s2.begin(), s2.end()) == vec_t({0,1,2}));
            REQUIRE(vec_t(s3.begin(), s3.end()) == vec_t({2,1,0}));
        }

        {
            auto s0 = set_t{0,1,2};
            auto s1 = s0;
            REQUIRE(s0 == set_t{0,1,2});
            REQUIRE(s1 == set_t{0,1,2});
            auto s2 = std::move(s1);
            REQUIRE(s1.empty());
            REQUIRE(s2 == set_t{0,1,2});
            auto s3 = set_t(s2, alloc_t());
            REQUIRE(s2 == s3);
            auto s4 = set_t(std::move(s3), alloc_t());
            REQUIRE(s3.empty());
            REQUIRE(s4 == set_t{0,1,2});
        }

        {
            auto s0 = set_t{0,1,2};
            set_t s1;
            s1 = s0;
            REQUIRE(s0 == set_t{0,1,2});
            REQUIRE(s1 == set_t{0,1,2});
            set_t s2;
            s2 = std::move(s1);
            REQUIRE(s0 == set_t{0,1,2});
            REQUIRE(s1.empty());
            REQUIRE(s2 == set_t{0,1,2});
            set_t s3;
            s3 = {1,2,3};
            REQUIRE(s3 == set_t{1,2,3});
        }

        {
            auto s0 = set_t(sorted_range, {1,2,2,3});
            REQUIRE(s0 == set_t{1,2,2,3});

            vec_t v1({1,2,3,3});
            auto s1 = set_t(sorted_range, v1.begin(), v1.end());
            REQUIRE(s1 == set_t{1,2,3,3});
        }
    }
    SUBCASE("capacity") {
        using set_t = flat_multiset<int>;

        {
            set_t s0;

            REQUIRE(s0.empty());
            REQUIRE_FALSE(s0.size());
            REQUIRE(s0.max_size() == std::vector<int>().max_size());

            s0.insert(42);

            REQUIRE_FALSE(s0.empty());
            REQUIRE(s0.size() == 1u);
            REQUIRE(s0.max_size() == std::vector<int>().max_size());

            s0.insert(42);
            REQUIRE(s0.size() == 2u);

            s0.insert(84);
            REQUIRE(s0.size() == 3u);

            s0.clear();

            REQUIRE(s0.empty());
            REQUIRE_FALSE(s0.size());
            REQUIRE(s0.max_size() == std::vector<int>().max_size());
        }

        {
            set_t s0;

            REQUIRE(s0.capacity() == 0);
            s0.reserve(42);
            REQUIRE(s0.capacity() == 42);
            s0.insert({1,2,3});
            REQUIRE(s0.capacity() == 42);
            s0.shrink_to_fit();
            REQUIRE(s0.size() == 3);
            REQUIRE(s0.capacity() == 3);
            REQUIRE(s0 == set_t{1,2,3});

            using alloc2_t = std::allocator<int>;

            using set2_t = flat_multiset<
                int,
                std::less<int>,
                std::deque<int, alloc2_t>>;

            set2_t s1;
            s1.insert({1,2,3});
            REQUIRE(s1 == set2_t{1,2,3});
        }
    }
    SUBCASE("inserts") {
        struct obj_t {
            obj_t(int ni) : i(ni) {}
            int i;

            [[maybe_unused]]
            bool operator<(const obj_t& o) const {
                return i < o.i;
            }

            [[maybe_unused]]
            bool operator==(const obj_t& o) const {
                return i == o.i;
            }
        };

        using set_t = flat_multiset<obj_t>;

        {
            set_t s0;

            auto i0 = s0.insert(1); // 1
            REQUIRE(s0 == set_t{1});
            REQUIRE(i0 == s0.begin());

            auto i1 = s0.insert(obj_t(1)); // 1,1
            REQUIRE(s0 == set_t{1,1});
            REQUIRE(i1 == s0.begin() + 1);

            auto i2 = s0.insert(obj_t(2)); // 1,1,2
            REQUIRE(s0 == set_t{1,1,2});
            REQUIRE(i2 == s0.begin() + 2);

            auto o2 = obj_t(2);
            auto i3 = s0.insert(o2); // 1,1,2,2
            REQUIRE(i3 == s0.begin() + 3);

            s0.insert(s0.cbegin(), 1); // 1,1,1,2,2
            s0.insert(s0.cbegin(), 2); // 1,1,1,2,2,2
            s0.insert(s0.cend(), 1); // 1,1,1,1,2,2,2
            s0.insert(s0.cend(), 2); // 1,1,1,1,2,2,2,2
            REQUIRE(s0 == set_t{1,1,1,1,2,2,2,2});

            s0.insert(s0.cbegin(), 0); // 0,1,1,1,1,2,2,2,2
            REQUIRE(s0 == set_t{0,1,1,1,1,2,2,2,2});
            s0.insert(s0.cend(), 3); // 0,1,1,1,1,2,2,2,2,3
            REQUIRE(s0 == set_t{0,1,1,1,1,2,2,2,2,3});
            s0.insert(s0.cbegin(), 4); // 0,1,1,1,1,2,2,2,2,3,4
            s0.insert(s0.cend(), -1); // -1,0,1,1,1,1,2,2,2,2,3,4
            REQUIRE(s0 == set_t{-1,0,1,1,1,1,2,2,2,2,3,4});

            s0.insert(s0.cbegin() + 2, obj_t(5)); // -1,0,1,1,1,1,2,2,2,2,3,4,5
            REQUIRE(s0 == set_t{-1,0,1,1,1,1,2,2,2,2,3,4,5});
            s0.insert(s0.cbegin(), obj_t(-2)); // -2,-1,0,1,1,1,1,2,2,2,2,3,4,5
            REQUIRE(s0 == set_t{-2,-1,0,1,1,1,1,2,2,2,2,3,4,5});
        }

        {
            set_t s0;

            auto e0 = s0.emplace(3); // 3
            REQUIRE(s0 == set_t{3});
            REQUIRE(e0 == s0.begin());

            auto e1 = s0.emplace(obj_t(3)); // 3,3
            REQUIRE(e1 == s0.begin() + 1);

            auto e2 = s0.emplace(4); // 3,3,4
            REQUIRE(s0 == set_t{3,3,4});
            REQUIRE(e2 == s0.begin() + 2);

            auto e3 = s0.emplace_hint(s0.cbegin(), 1); // 1,3,3,4
            REQUIRE(e3 == s0.begin());
            auto e4 = s0.emplace_hint(s0.cend(), 2); // 1,2,3,3,4
            REQUIRE(e4 == s0.begin() + 1);
            s0.emplace_hint(s0.cbegin(), 5); // 1,2,3,3,4,5
            s0.emplace_hint(s0.cend(), 6); // 1,2,3,3,4,5,6
            REQUIRE(s0 == set_t{1,2,3,3,4,5,6});
        }

        {
            set_t s0;
            s0.insert({6,4,2,4});
            REQUIRE(s0 == set_t{2,4,4,6});
            s0.insert({9,7,3,5,5});
            REQUIRE(s0 == set_t{2,3,4,4,5,5,6,7,9});
        }

        {
            set_t s0;
            s0.insert(sorted_unique_range, {1,2,3});
            REQUIRE(s0 == set_t{1,2,3});

            set_t s1;
            s1.insert(sorted_range, {1,2,2,3});
            REQUIRE(s1 == set_t{1,2,2,3});
        }
    }
    SUBCASE("erasers") {
        using set_t = flat_multiset<int>;
        {
            set_t s0{1,2,3,4,5};
            s0.clear();
            REQUIRE(s0.empty());
        }
        {
            set_t s0{1,2,3,4,5};
            auto i = s0.erase(s0.find(3));
            REQUIRE(i == s0.begin() + 2);
            REQUIRE(s0 == set_t{1,2,4,5});
        }
        {
            set_t s0{1,2,3,4,5};
            auto i = s0.erase(s0.begin() + 2, s0.end());
            REQUIRE(i == s0.end());
            REQUIRE(s0 == set_t{1,2});
        }
        {
            set_t s0{1,2,3,3,4,5};
            REQUIRE(s0.erase(2) == 1);
            REQUIRE(s0.erase(3) == 2);
            REQUIRE(s0.erase(6) == 0);
            REQUIRE(s0 == set_t{1,4,5});
        }
        {
            set_t s0{1,2,3};
            set_t s1{3,4,5};
            s0.swap(s1);
            REQUIRE(s0 == set_t{3,4,5});
            REQUIRE(s1 == set_t{1,2,3});
            swap(s1, s0);
            REQUIRE(s0 == set_t{1,2,3});
            REQUIRE(s1 == set_t{3,4,5});
        }
    }
    SUBCASE("lookup") {
        using set_t = flat_multiset<int>;
        {
            set_t s0{1,2,3,3,4,5};
            REQUIRE(s0.count(2) == 1);
            REQUIRE(s0.count(3) == 2);
            REQUIRE_FALSE(s0.count(6));
            REQUIRE(my_as_const(s0).count(5));
            REQUIRE_FALSE(my_as_const(s0).count(0));
        }
        {
            set_t s0{1,2,3,4,5};
            REQUIRE(s0.find(2) == s0.begin() + 1);
            REQUIRE(my_as_const(s0).find(3) == s0.cbegin() + 2);
            REQUIRE(s0.find(6) == s0.end());
            REQUIRE(my_as_const(s0).find(0) == s0.cend());
            REQUIRE(my_as_const(s0).contains(1));
            REQUIRE(my_as_const(s0).contains(3));
            REQUIRE_FALSE(my_as_const(s0).contains(0));
        }
        {
            set_t s0{1,2,3,3,4,5};
            REQUIRE(s0.equal_range(3) == std::make_pair(s0.begin() + 2, s0.begin() + 4));
            REQUIRE(s0.equal_range(6) == std::make_pair(s0.end(), s0.end()));
            REQUIRE(my_as_const(s0).equal_range(3) == std::make_pair(s0.cbegin() + 2, s0.cbegin() + 4));
            REQUIRE(my_as_const(s0).equal_range(0) == std::make_pair(s0.cbegin(), s0.cbegin()));
        }
        {
            set_t s0{0,0,3,6,9};
            REQUIRE(s0.lower_bound(0) == s0.begin());
            REQUIRE(s0.lower_bound(1) == s0.begin() + 2);
            REQUIRE(s0.lower_bound(10) == s0.end());
            REQUIRE(my_as_const(s0).lower_bound(-1) == s0.cbegin());
            REQUIRE(my_as_const(s0).lower_bound(7) == s0.cbegin() + 4);
        }
    }
    SUBCASE("heterogeneous") {
        flat_multiset<std::string, std::less<>> s0{"hello", "world"};
        REQUIRE(s0.find(std::string_view("hello")) == s0.begin());
        REQUIRE(my_as_const(s0).find(std::string_view("world")) == s0.begin() + 1);
        REQUIRE(s0.find(std::string_view("42")) == s0.end());
        REQUIRE(my_as_const(s0).find(std::string_view("42")) == s0.cend());

        REQUIRE(my_as_const(s0).contains(std::string_view("hello")));
        REQUIRE_FALSE(my_as_const(s0).contains(std::string_view("42")));

        REQUIRE(my_as_const(s0).count(std::string_view("hello")) == 1);
        REQUIRE(my_as_const(s0).count(std::string_view("hello_42")) == 0);

        REQUIRE(s0.upper_bound(std::string_view("hello")) == s0.begin() + 1);
        REQUIRE(my_as_const(s0).upper_bound(std::string_view("hello")) == s0.begin() + 1);
    }
    SUBCASE("observers") {
        struct my_less {
            int i;
            my_less(int ni) : i(ni) {}
            [[maybe_unused]] bool operator()(int l, int r) const {
                return l < r;
            }
        };
        using set_t = flat_multiset<int, my_less>;
        set_t s0(my_less(42));
        REQUIRE(my_as_const(s0).key_comp().i == 42);
        REQUIRE(my_as_const(s0).value_comp().i == 42);
    }
    SUBCASE("custom_less") {
        using set_t = flat_multiset<int, dummy_less<int>>;
        auto s0 = set_t(dummy_less<int>(42));
        auto s1 = set_t(dummy_less<int>(21));
        REQUIRE(s0.key_comp().i == 42);
        REQUIRE(s1.key_comp().i == 21);
        s0.swap(s1);
        REQUIRE(s0.key_comp().i == 21);
        REQUIRE(s1.key_comp().i == 42);
    }
    SUBCASE("operators") {
        using set_t = flat_multiset<int>;

        REQUIRE(set_t{1,2,3} == set_t{3,2,1});
        REQUIRE_FALSE(set_t{1,2,3} == set_t{3,2,4});
        REQUIRE_FALSE(set_t{1,2,3} == set_t{1,2,3,4});

        REQUIRE(set_t{1,2,3} != set_t{3,2,4});
        REQUIRE_FALSE(set_t{1,2,3} != set_t{3,2,1});

        REQUIRE(set_t{2,3,4,6} < set_t{2,3,5});
        REQUIRE(set_t{2,3,4,6} <= set_t{2,3,5});
        REQUIRE_FALSE(set_t{2,3,5} < set_t{2,3,4,6});
        REQUIRE_FALSE(set_t{2,3,5} <= set_t{2,3,4,6});

        REQUIRE_FALSE(set_t{2,3,4,6} > set_t{2,3,5});
        REQUIRE_FALSE(set_t{2,3,4,6} >= set_t{2,3,5});
        REQUIRE(set_t{2,3,5} > set_t{2,3,4,6});
        REQUIRE(set_t{2,3,5} >= set_t{2,3,4,6});

        REQUIRE_FALSE(set_t{1,2,3} < set_t{1,2,3});
        REQUIRE(set_t{1,2,3} <= set_t{1,2,3});
        REQUIRE_FALSE(set_t{1,2,3} > set_t{1,2,3});
        REQUIRE(set_t{1,2,3} >= set_t{1,2,3});

        const set_t s0;
        REQUIRE(s0 == s0);
        REQUIRE_FALSE(s0 != s0);
        REQUIRE_FALSE(s0 < s0);
        REQUIRE_FALSE(s0 > s0);
        REQUIRE(s0 <= s0);
        REQUIRE(s0 >= s0);
    }
}