tests/src/unit-modifiers.cpp

//     __ _____ _____ _____
//  __|  |   __|     |   | |  JSON for Modern C++ (supporting code)
// |  |  |__   |  |  | | | |  version 3.11.3
// |_____|_____|_____|_|___|  https://github.com/nlohmann/json
//
// Copyright (c) 2013-2022 Niels Lohmann <http://nlohmann.me>.
// SPDX-FileCopyrightText: 2013-2023 Niels Lohmann <https://nlohmann.me>
// SPDX-License-Identifier: MIT

#include "doctest_compatibility.h"

#include <nlohmann/json.hpp>
using nlohmann::json;

TEST_CASE("modifiers")
{
    SECTION("clear()")
    {
        SECTION("boolean")
        {
            json j = true;
            json const k = j;

            j.clear();
            CHECK(j == json(json::value_t::boolean));
            CHECK(j == json(k.type()));
        }

        SECTION("string")
        {
            json j = "hello world";
            json const k = j;

            j.clear();
            CHECK(j == json(json::value_t::string));
            CHECK(j == json(k.type()));
        }

        SECTION("array")
        {
            SECTION("empty array")
            {
                json j = json::array();
                json const k = j;

                j.clear();
                CHECK(j.empty());
                CHECK(j == json(json::value_t::array));
                CHECK(j == json(k.type()));
            }

            SECTION("filled array")
            {
                json j = { 1, 2, 3 };
                json const k = j;

                j.clear();
                CHECK(j.empty());
                CHECK(j == json(json::value_t::array));
                CHECK(j == json(k.type()));
            }
        }

        SECTION("object")
        {
            SECTION("empty object")
            {
                json j = json::object();
                json const k = j;

                j.clear();
                CHECK(j.empty());
                CHECK(j == json(json::value_t::object));
                CHECK(j == json(k.type()));
            }

            SECTION("filled object")
            {
                json j = { { "one", 1 }, { "two", 2 }, { "three", 3 } };
                json const k = j;

                j.clear();
                CHECK(j.empty());
                CHECK(j == json(json::value_t::object));
                CHECK(j == json(k.type()));
            }
        }

        SECTION("binary")
        {
            SECTION("empty binary")
            {
                json j = json::binary({});
                json const k = j;

                j.clear();
                CHECK(!j.empty());
                CHECK(j == json(json::value_t::binary));
                CHECK(j == json(k.type()));
            }

            SECTION("filled binary")
            {
                json j = json::binary({ 1, 2, 3, 4, 5 });
                json const k = j;

                j.clear();
                CHECK(!j.empty());
                CHECK(j == json(json::value_t::binary));
                CHECK(j == json(k.type()));
            }
        }

        SECTION("number (integer)")
        {
            json j = 23;
            json const k = j;

            j.clear();
            CHECK(j == json(json::value_t::number_integer));
            CHECK(j == json(k.type()));
        }

        SECTION("number (unsigned)")
        {
            json j = 23u;
            json const k = j;

            j.clear();
            CHECK(j == json(json::value_t::number_integer));
            CHECK(j == json(k.type()));
        }

        SECTION("number (float)")
        {
            json j = 23.42;
            json const k = j;

            j.clear();
            CHECK(j == json(json::value_t::number_float));
            CHECK(j == json(k.type()));
        }

        SECTION("null")
        {
            json j = nullptr;
            json const k = j;

            j.clear();
            CHECK(j == json(json::value_t::null));
            CHECK(j == json(k.type()));
        }
    }

    SECTION("push_back()")
    {
        SECTION("to array")
        {
            SECTION("json&&")
            {
                SECTION("null")
                {
                    json j;
                    j.push_back(1);
                    j.push_back(2);
                    CHECK(j.type() == json::value_t::array);
                    CHECK(j == json({ 1, 2 }));
                }

                SECTION("array")
                {
                    json j = { 1, 2, 3 };
                    j.push_back("Hello");
                    CHECK(j.type() == json::value_t::array);
                    CHECK(j == json({ 1, 2, 3, "Hello" }));
                }

                SECTION("other type")
                {
                    json j = 1;
                    CHECK_THROWS_WITH_AS(j.push_back("Hello"), "[json.exception.type_error.308] cannot use push_back() with number", json::type_error&);
                }
            }

            SECTION("const json&")
            {
                SECTION("null")
                {
                    json j;
                    json const k(1);
                    j.push_back(k);
                    j.push_back(k);
                    CHECK(j.type() == json::value_t::array);
                    CHECK(j == json({ 1, 1 }));
                }

                SECTION("array")
                {
                    json j = { 1, 2, 3 };
                    json const k("Hello");
                    j.push_back(k);
                    CHECK(j.type() == json::value_t::array);
                    CHECK(j == json({ 1, 2, 3, "Hello" }));
                }

                SECTION("other type")
                {
                    json j = 1;
                    json const k("Hello");
                    CHECK_THROWS_WITH_AS(j.push_back(k), "[json.exception.type_error.308] cannot use push_back() with number", json::type_error&);
                }
            }
        }

        SECTION("to object")
        {
            SECTION("null")
            {
                json j;
                j.push_back(json::object_t::value_type({ "one", 1 }));
                j.push_back(json::object_t::value_type({ "two", 2 }));
                CHECK(j.type() == json::value_t::object);
                CHECK(j.size() == 2);
                CHECK(j["one"] == json(1));
                CHECK(j["two"] == json(2));
            }

            SECTION("object")
            {
                json j(json::value_t::object);
                j.push_back(json::object_t::value_type({ "one", 1 }));
                j.push_back(json::object_t::value_type({ "two", 2 }));
                CHECK(j.size() == 2);
                CHECK(j["one"] == json(1));
                CHECK(j["two"] == json(2));
            }

            SECTION("other type")
            {
                json j = 1;
                json const k("Hello");
                CHECK_THROWS_WITH_AS(j.push_back(json::object_t::value_type({ "one", 1 })),
                                     "[json.exception.type_error.308] cannot use push_back() with number",
                                     json::type_error&);
            }
        }

        SECTION("with initializer_list")
        {
            SECTION("null")
            {
                json j;
                j.push_back({ "foo", "bar" });
                CHECK(j == json::array({ { "foo", "bar" } }));

                json k;
                k.push_back({ 1, 2, 3 });
                CHECK(k == json::array({ { 1, 2, 3 } }));
            }

            SECTION("array")
            {
                json j = { 1, 2, 3 };
                j.push_back({ "foo", "bar" });
                CHECK(j == json({ 1, 2, 3, { "foo", "bar" } }));

                json k = { 1, 2, 3 };
                k.push_back({ 1, 2, 3 });
                CHECK(k == json({ 1, 2, 3, { 1, 2, 3 } }));
            }

            SECTION("object")
            {
                json j = { { "key1", 1 } };
                j.push_back({ "key2", "bar" });
                CHECK(j == json({ { "key1", 1 }, { "key2", "bar" } }));

                // invalid values (no string/val pair)
                CHECK_THROWS_WITH_AS(j.push_back({ 1 }), "[json.exception.type_error.308] cannot use push_back() with object", json::type_error&);
                CHECK_THROWS_WITH_AS(j.push_back({ 1, 2 }), "[json.exception.type_error.308] cannot use push_back() with object", json::type_error&);
                CHECK_THROWS_WITH_AS(j.push_back({ 1, 2, 3, 4 }), "[json.exception.type_error.308] cannot use push_back() with object", json::type_error&);
            }
        }
    }

    SECTION("emplace_back()")
    {
        SECTION("to array")
        {
            SECTION("null")
            {
                json j;
                auto& x1 = j.emplace_back(1);
                CHECK(x1 == 1);
                auto& x2 = j.emplace_back(2);
                CHECK(x2 == 2);
                CHECK(j.type() == json::value_t::array);
                CHECK(j == json({ 1, 2 }));
            }

            SECTION("array")
            {
                json j = { 1, 2, 3 };
                auto& x = j.emplace_back("Hello");
                CHECK(x == "Hello");
                CHECK(j.type() == json::value_t::array);
                CHECK(j == json({ 1, 2, 3, "Hello" }));
            }

            SECTION("multiple values")
            {
                json j;
                auto& x = j.emplace_back(3, "foo");
                CHECK(x == json({ "foo", "foo", "foo" }));
                CHECK(j.type() == json::value_t::array);
                CHECK(j == json({ { "foo", "foo", "foo" } }));
            }
        }

        SECTION("other type")
        {
            json j = 1;
            CHECK_THROWS_WITH_AS(j.emplace_back("Hello"), "[json.exception.type_error.311] cannot use emplace_back() with number", json::type_error&);
        }
    }

    SECTION("emplace()")
    {
        SECTION("to object")
        {
            SECTION("null")
            {
                // start with a null value
                json j;

                // add a new key
                auto res1 = j.emplace("foo", "bar");
                CHECK(res1.second == true);
                CHECK(*res1.first == "bar");

                // the null value is changed to an object
                CHECK(j.type() == json::value_t::object);

                // add a new key
                auto res2 = j.emplace("baz", "bam");
                CHECK(res2.second == true);
                CHECK(*res2.first == "bam");

                // we try to insert at given key - no change
                auto res3 = j.emplace("baz", "bad");
                CHECK(res3.second == false);
                CHECK(*res3.first == "bam");

                // the final object
                CHECK(j == json({ { "baz", "bam" }, { "foo", "bar" } }));
            }

            SECTION("object")
            {
                // start with an object
                json j = { { "foo", "bar" } };

                // add a new key
                auto res1 = j.emplace("baz", "bam");
                CHECK(res1.second == true);
                CHECK(*res1.first == "bam");

                // add an existing key
                auto res2 = j.emplace("foo", "bad");
                CHECK(res2.second == false);
                CHECK(*res2.first == "bar");

                // check final object
                CHECK(j == json({ { "baz", "bam" }, { "foo", "bar" } }));
            }
        }

        SECTION("other type")
        {
            json j = 1;
            CHECK_THROWS_WITH_AS(j.emplace("foo", "bar"), "[json.exception.type_error.311] cannot use emplace() with number", json::type_error&);
        }
    }

    SECTION("operator+=")
    {
        SECTION("to array")
        {
            SECTION("json&&")
            {
                SECTION("null")
                {
                    json j;
                    j += 1;
                    j += 2;
                    CHECK(j.type() == json::value_t::array);
                    CHECK(j == json({ 1, 2 }));
                }

                SECTION("array")
                {
                    json j = { 1, 2, 3 };
                    j += "Hello";
                    CHECK(j.type() == json::value_t::array);
                    CHECK(j == json({ 1, 2, 3, "Hello" }));
                }

                SECTION("other type")
                {
                    json j = 1;
                    CHECK_THROWS_WITH_AS(j += "Hello", "[json.exception.type_error.308] cannot use push_back() with number", json::type_error&);
                }
            }

            SECTION("const json&")
            {
                SECTION("null")
                {
                    json j;
                    json const k(1);
                    j += k;
                    j += k;
                    CHECK(j.type() == json::value_t::array);
                    CHECK(j == json({ 1, 1 }));
                }

                SECTION("array")
                {
                    json j = { 1, 2, 3 };
                    json const k("Hello");
                    j += k;
                    CHECK(j.type() == json::value_t::array);
                    CHECK(j == json({ 1, 2, 3, "Hello" }));
                }

                SECTION("other type")
                {
                    json j = 1;
                    json const k("Hello");
                    CHECK_THROWS_WITH_AS(j += k, "[json.exception.type_error.308] cannot use push_back() with number", json::type_error&);
                }
            }
        }

        SECTION("to object")
        {
            SECTION("null")
            {
                json j;
                j += json::object_t::value_type({ "one", 1 });
                j += json::object_t::value_type({ "two", 2 });
                CHECK(j.type() == json::value_t::object);
                CHECK(j.size() == 2);
                CHECK(j["one"] == json(1));
                CHECK(j["two"] == json(2));
            }

            SECTION("object")
            {
                json j(json::value_t::object);
                j += json::object_t::value_type({ "one", 1 });
                j += json::object_t::value_type({ "two", 2 });
                CHECK(j.size() == 2);
                CHECK(j["one"] == json(1));
                CHECK(j["two"] == json(2));
            }

            SECTION("other type")
            {
                json j = 1;
                json const k("Hello");
                CHECK_THROWS_WITH_AS(j += json::object_t::value_type({ "one", 1 }),
                                     "[json.exception.type_error.308] cannot use push_back() with number",
                                     json::type_error&);
            }
        }

        SECTION("with initializer_list")
        {
            SECTION("null")
            {
                json j;
                j += { "foo", "bar" };
                CHECK(j == json::array({ { "foo", "bar" } }));

                json k;
                k += { 1, 2, 3 };
                CHECK(k == json::array({ { 1, 2, 3 } }));
            }

            SECTION("array")
            {
                json j = { 1, 2, 3 };
                j += { "foo", "bar" };
                CHECK(j == json({ 1, 2, 3, { "foo", "bar" } }));

                json k = { 1, 2, 3 };
                k += { 1, 2, 3 };
                CHECK(k == json({ 1, 2, 3, { 1, 2, 3 } }));
            }

            SECTION("object")
            {
                json j = { { "key1", 1 } };
                j += { "key2", "bar" };
                CHECK(j == json({ { "key1", 1 }, { "key2", "bar" } }));

                json k = { { "key1", 1 } };
                CHECK_THROWS_WITH_AS((k += { 1, 2, 3, 4 }), "[json.exception.type_error.308] cannot use push_back() with object", json::type_error&);
            }
        }
    }

    SECTION("insert()")
    {
        json j_array = { 1, 2, 3, 4 };
        json j_value = 5;

        SECTION("value at position")
        {
            SECTION("insert before begin()")
            {
                auto it = j_array.insert(j_array.begin(), j_value);
                CHECK(j_array.size() == 5);
                CHECK(*it == j_value);
                CHECK(j_array.begin() == it);
                CHECK(j_array == json({ 5, 1, 2, 3, 4 }));
            }

            SECTION("insert in the middle")
            {
                auto it = j_array.insert(j_array.begin() + 2, j_value);
                CHECK(j_array.size() == 5);
                CHECK(*it == j_value);
                CHECK((it - j_array.begin()) == 2);
                CHECK(j_array == json({ 1, 2, 5, 3, 4 }));
            }

            SECTION("insert before end()")
            {
                auto it = j_array.insert(j_array.end(), j_value);
                CHECK(j_array.size() == 5);
                CHECK(*it == j_value);
                CHECK((j_array.end() - it) == 1);
                CHECK(j_array == json({ 1, 2, 3, 4, 5 }));
            }
        }

        SECTION("rvalue at position")
        {
            SECTION("insert before begin()")
            {
                auto it = j_array.insert(j_array.begin(), 5);
                CHECK(j_array.size() == 5);
                CHECK(*it == j_value);
                CHECK(j_array.begin() == it);
                CHECK(j_array == json({ 5, 1, 2, 3, 4 }));
            }

            SECTION("insert in the middle")
            {
                auto it = j_array.insert(j_array.begin() + 2, 5);
                CHECK(j_array.size() == 5);
                CHECK(*it == j_value);
                CHECK((it - j_array.begin()) == 2);
                CHECK(j_array == json({ 1, 2, 5, 3, 4 }));
            }

            SECTION("insert before end()")
            {
                auto it = j_array.insert(j_array.end(), 5);
                CHECK(j_array.size() == 5);
                CHECK(*it == j_value);
                CHECK((j_array.end() - it) == 1);
                CHECK(j_array == json({ 1, 2, 3, 4, 5 }));
            }
        }

        SECTION("copies at position")
        {
            SECTION("insert before begin()")
            {
                auto it = j_array.insert(j_array.begin(), 3, 5);
                CHECK(j_array.size() == 7);
                CHECK(*it == j_value);
                CHECK(j_array.begin() == it);
                CHECK(j_array == json({ 5, 5, 5, 1, 2, 3, 4 }));
            }

            SECTION("insert in the middle")
            {
                auto it = j_array.insert(j_array.begin() + 2, 3, 5);
                CHECK(j_array.size() == 7);
                CHECK(*it == j_value);
                CHECK((it - j_array.begin()) == 2);
                CHECK(j_array == json({ 1, 2, 5, 5, 5, 3, 4 }));
            }

            SECTION("insert before end()")
            {
                auto it = j_array.insert(j_array.end(), 3, 5);
                CHECK(j_array.size() == 7);
                CHECK(*it == j_value);
                CHECK((j_array.end() - it) == 3);
                CHECK(j_array == json({ 1, 2, 3, 4, 5, 5, 5 }));
            }

            SECTION("insert nothing (count = 0)")
            {
                auto it = j_array.insert(j_array.end(), 0, 5);
                CHECK(j_array.size() == 4);
                // the returned iterator points to the first inserted element;
                // there were 4 elements, so it should point to the 5th
                CHECK(it == j_array.begin() + 4);
                CHECK(j_array == json({ 1, 2, 3, 4 }));
            }
        }

        SECTION("range for array")
        {
            json j_other_array = { "first", "second" };

            SECTION("proper usage")
            {
                auto it = j_array.insert(j_array.end(), j_other_array.begin(), j_other_array.end());
                CHECK(j_array.size() == 6);
                CHECK(*it == *j_other_array.begin());
                CHECK((j_array.end() - it) == 2);
                CHECK(j_array == json({ 1, 2, 3, 4, "first", "second" }));
            }

            SECTION("empty range")
            {
                auto it = j_array.insert(j_array.end(), j_other_array.begin(), j_other_array.begin());
                CHECK(j_array.size() == 4);
                CHECK(it == j_array.end());
                CHECK(j_array == json({ 1, 2, 3, 4 }));
            }

            SECTION("invalid iterators")
            {
                json j_other_array2 = { "first", "second" };

                CHECK_THROWS_WITH_AS(j_array.insert(j_array.end(), j_array.begin(), j_array.end()),
                                     "[json.exception.invalid_iterator.211] passed iterators may not belong to container",
                                     json::invalid_iterator&);
                CHECK_THROWS_WITH_AS(j_array.insert(j_array.end(), j_other_array.begin(), j_other_array2.end()),
                                     "[json.exception.invalid_iterator.210] iterators do not fit",
                                     json::invalid_iterator&);
            }
        }

        SECTION("range for object")
        {
            json j_object1 = { { "one", "eins" }, { "two", "zwei" } };
            json j_object2 = { { "eleven", "elf" }, { "seventeen", "siebzehn" } };

            SECTION("proper usage")
            {
                j_object1.insert(j_object2.begin(), j_object2.end());
                CHECK(j_object1.size() == 4);
            }

            SECTION("empty range")
            {
                j_object1.insert(j_object2.begin(), j_object2.begin());
                CHECK(j_object1.size() == 2);
            }

            SECTION("invalid iterators")
            {
                json const j_other_array2 = { "first", "second" };

                CHECK_THROWS_WITH_AS(j_array.insert(j_object2.begin(), j_object2.end()),
                                     "[json.exception.type_error.309] cannot use insert() with array",
                                     json::type_error&);
                CHECK_THROWS_WITH_AS(j_object1.insert(j_object1.begin(), j_object2.end()),
                                     "[json.exception.invalid_iterator.210] iterators do not fit",
                                     json::invalid_iterator&);
                CHECK_THROWS_WITH_AS(j_object1.insert(j_array.begin(), j_array.end()),
                                     "[json.exception.invalid_iterator.202] iterators first and last must point to objects",
                                     json::invalid_iterator&);
            }
        }

        SECTION("initializer list at position")
        {
            SECTION("insert before begin()")
            {
                auto it = j_array.insert(j_array.begin(), { 7, 8, 9 });
                CHECK(j_array.size() == 7);
                CHECK(*it == json(7));
                CHECK(j_array.begin() == it);
                CHECK(j_array == json({ 7, 8, 9, 1, 2, 3, 4 }));
            }

            SECTION("insert in the middle")
            {
                auto it = j_array.insert(j_array.begin() + 2, { 7, 8, 9 });
                CHECK(j_array.size() == 7);
                CHECK(*it == json(7));
                CHECK((it - j_array.begin()) == 2);
                CHECK(j_array == json({ 1, 2, 7, 8, 9, 3, 4 }));
            }

            SECTION("insert before end()")
            {
                auto it = j_array.insert(j_array.end(), { 7, 8, 9 });
                CHECK(j_array.size() == 7);
                CHECK(*it == json(7));
                CHECK((j_array.end() - it) == 3);
                CHECK(j_array == json({ 1, 2, 3, 4, 7, 8, 9 }));
            }
        }

        SECTION("invalid iterator")
        {
            // pass iterator to a different array
            json j_another_array = { 1, 2 };
            json j_yet_another_array = { "first", "second" };
            CHECK_THROWS_WITH_AS(j_array.insert(j_another_array.end(), 10),
                                 "[json.exception.invalid_iterator.202] iterator does not fit current value",
                                 json::invalid_iterator&);
            CHECK_THROWS_WITH_AS(j_array.insert(j_another_array.end(), j_value),
                                 "[json.exception.invalid_iterator.202] iterator does not fit current value",
                                 json::invalid_iterator&);
            CHECK_THROWS_WITH_AS(j_array.insert(j_another_array.end(), 10, 11),
                                 "[json.exception.invalid_iterator.202] iterator does not fit current value",
                                 json::invalid_iterator&);
            CHECK_THROWS_WITH_AS(j_array.insert(j_another_array.end(), j_yet_another_array.begin(), j_yet_another_array.end()),
                                 "[json.exception.invalid_iterator.202] iterator does not fit current value",
                                 json::invalid_iterator&);
            CHECK_THROWS_WITH_AS(j_array.insert(j_another_array.end(), { 1, 2, 3, 4 }),
                                 "[json.exception.invalid_iterator.202] iterator does not fit current value",
                                 json::invalid_iterator&);
        }

        SECTION("non-array type")
        {
            // call insert on a non-array type
            json j_nonarray = 3;
            json j_yet_another_array = { "first", "second" };
            CHECK_THROWS_WITH_AS(j_nonarray.insert(j_nonarray.end(), 10), "[json.exception.type_error.309] cannot use insert() with number", json::type_error&);
            CHECK_THROWS_WITH_AS(j_nonarray.insert(j_nonarray.end(), j_value),
                                 "[json.exception.type_error.309] cannot use insert() with number",
                                 json::type_error&);
            CHECK_THROWS_WITH_AS(j_nonarray.insert(j_nonarray.end(), 10, 11),
                                 "[json.exception.type_error.309] cannot use insert() with number",
                                 json::type_error&);
            CHECK_THROWS_WITH_AS(j_nonarray.insert(j_nonarray.end(), j_yet_another_array.begin(), j_yet_another_array.end()),
                                 "[json.exception.type_error.309] cannot use insert() with number",
                                 json::type_error&);
            CHECK_THROWS_WITH_AS(j_nonarray.insert(j_nonarray.end(), { 1, 2, 3, 4 }),
                                 "[json.exception.type_error.309] cannot use insert() with number",
                                 json::type_error&);
        }
    }

    SECTION("update()")
    {
        SECTION("non-recursive (default)")
        {
            json j_object1 = { { "one", "eins" }, { "two", "zwei" } };
            json j_object2 = { { "three", "drei" }, { "two", "zwo" } };
            json j_array = { 1, 2, 3, 4 };

            SECTION("const reference")
            {
                SECTION("proper usage")
                {
                    j_object1.update(j_object2);
                    CHECK(j_object1 == json({ { "one", "eins" }, { "two", "zwo" }, { "three", "drei" } }));

                    json j_null;
                    j_null.update(j_object2);
                    CHECK(j_null == j_object2);
                }

                SECTION("wrong types")
                {
                    CHECK_THROWS_WITH_AS(j_array.update(j_object1), "[json.exception.type_error.312] cannot use update() with array", json::type_error&);

                    CHECK_THROWS_WITH_AS(j_object1.update(j_array), "[json.exception.type_error.312] cannot use update() with array", json::type_error&);
                }
            }

            SECTION("iterator range")
            {
                SECTION("proper usage")
                {
                    j_object1.update(j_object2.begin(), j_object2.end());
                    CHECK(j_object1 == json({ { "one", "eins" }, { "two", "zwo" }, { "three", "drei" } }));

                    json j_null;
                    j_null.update(j_object2.begin(), j_object2.end());
                    CHECK(j_null == j_object2);
                }

                SECTION("empty range")
                {
                    j_object1.update(j_object2.begin(), j_object2.begin());
                    CHECK(j_object1 == json({ { "one", "eins" }, { "two", "zwei" } }));
                }

                SECTION("invalid iterators")
                {
                    json const j_other_array2 = { "first", "second" };

                    CHECK_THROWS_WITH_AS(j_array.update(j_object2.begin(), j_object2.end()),
                                         "[json.exception.type_error.312] cannot use update() with array",
                                         json::type_error&);
                    CHECK_THROWS_WITH_AS(j_object1.update(j_object1.begin(), j_object2.end()),
                                         "[json.exception.invalid_iterator.210] iterators do not fit",
                                         json::invalid_iterator&);
                    CHECK_THROWS_WITH_AS(j_object1.update(j_array.begin(), j_array.end()),
                                         "[json.exception.type_error.312] cannot use update() with array",
                                         json::type_error&);
                }
            }
        }

        SECTION("recursive")
        {
            SECTION("const reference")
            {
                SECTION("extend object")
                {
                    json j1 = { { "string", "s" }, { "numbers", { { "one", 1 } } } };
                    json const j2 = { { "string", "t" }, { "numbers", { { "two", 2 } } } };
                    j1.update(j2, true);
                    CHECK(j1 == json({ { "string", "t" }, { "numbers", { { "one", 1 }, { "two", 2 } } } }));
                }

                SECTION("replace object")
                {
                    json j1 = { { "string", "s" }, { "numbers", { { "one", 1 } } } };
                    json const j2 = { { "string", "t" }, { "numbers", 1 } };
                    j1.update(j2, true);
                    CHECK(j1 == json({ { "string", "t" }, { "numbers", 1 } }));
                }
            }
        }
    }

    SECTION("swap()")
    {
        SECTION("json")
        {
            SECTION("member swap")
            {
                json j("hello world");
                json k(42.23);

                j.swap(k);

                CHECK(j == json(42.23));
                CHECK(k == json("hello world"));
            }

            SECTION("nonmember swap")
            {
                json j("hello world");
                json k(42.23);

                using std::swap;
                swap(j, k);

                CHECK(j == json(42.23));
                CHECK(k == json("hello world"));
            }
        }

        SECTION("array_t")
        {
            SECTION("array_t type")
            {
                json j = { 1, 2, 3, 4 };
                json::array_t a = { "foo", "bar", "baz" };

                j.swap(a);

                CHECK(j == json({ "foo", "bar", "baz" }));

                j.swap(a);

                CHECK(j == json({ 1, 2, 3, 4 }));
            }

            SECTION("non-array_t type")
            {
                json j = 17;
                json::array_t a = { "foo", "bar", "baz" };

                CHECK_THROWS_WITH_AS(j.swap(a), "[json.exception.type_error.310] cannot use swap(array_t&) with number", json::type_error&);
            }
        }

        SECTION("object_t")
        {
            SECTION("object_t type")
            {
                json j = { { "one", 1 }, { "two", 2 } };
                json::object_t o = { { "cow", "Kuh" }, { "chicken", "Huhn" } };

                j.swap(o);

                CHECK(j == json({ { "cow", "Kuh" }, { "chicken", "Huhn" } }));

                j.swap(o);

                CHECK(j == json({ { "one", 1 }, { "two", 2 } }));
            }

            SECTION("non-object_t type")
            {
                json j = 17;
                json::object_t o = { { "cow", "Kuh" }, { "chicken", "Huhn" } };

                CHECK_THROWS_WITH_AS(j.swap(o), "[json.exception.type_error.310] cannot use swap(object_t&) with number", json::type_error&);
            }
        }

        SECTION("string_t")
        {
            SECTION("string_t type")
            {
                json j = "Hello world";
                json::string_t s = "Hallo Welt";

                j.swap(s);

                CHECK(j == json("Hallo Welt"));

                j.swap(s);

                CHECK(j == json("Hello world"));
            }

            SECTION("non-string_t type")
            {
                json j = 17;
                json::string_t s = "Hallo Welt";

                CHECK_THROWS_WITH_AS(j.swap(s), "[json.exception.type_error.310] cannot use swap(string_t&) with number", json::type_error&);
            }
        }

        SECTION("binary_t")
        {
            SECTION("binary_t type")
            {
                json j = json::binary({ 1, 2, 3, 4 });
                json::binary_t s = { { 5, 6, 7, 8 } };

                j.swap(s);

                CHECK(j == json::binary({ 5, 6, 7, 8 }));

                j.swap(s);

                CHECK(j == json::binary({ 1, 2, 3, 4 }));
            }

            SECTION("binary_t::container_type type")
            {
                json j = json::binary({ 1, 2, 3, 4 });
                std::vector<std::uint8_t> s = { { 5, 6, 7, 8 } };

                j.swap(s);

                CHECK(j == json::binary({ 5, 6, 7, 8 }));

                j.swap(s);

                CHECK(j == json::binary({ 1, 2, 3, 4 }));
            }

            SECTION("non-binary_t type")
            {
                json j = 17;
                json::binary_t s1 = { { 1, 2, 3, 4 } };
                std::vector<std::uint8_t> s2 = { { 5, 6, 7, 8 } };

                CHECK_THROWS_WITH_AS(j.swap(s1), "[json.exception.type_error.310] cannot use swap(binary_t&) with number", json::type_error);
                CHECK_THROWS_WITH_AS(j.swap(s2), "[json.exception.type_error.310] cannot use swap(binary_t::container_type&) with number", json::type_error);
            }
        }
    }
}