Add 'json4cpp/' from commit '9a737481aed085fd289f82dff1fa8c3c66627a7e'

git-subtree-dir: json4cpp
git-subtree-mainline: 292baed7ac0cf84263263966ed32ed113cae857f
git-subtree-split: 9a737481aed085fd289f82dff1fa8c3c66627a7e

1 files changed, 952 insertions, 0 deletions

diff --git a/json4cpp/tests/src/unit-modifiers.cpp b/json4cpp/tests/src/unit-modifiers.cpp
new file mode 100644
index 0000000000..18185ec00b
--- /dev/null
+++ b/json4cpp/tests/src/unit-modifiers.cpp
@@ -0,0 +1,952 @@
+//     __ _____ _____ _____
+//  __|  |   __|     |   | |  JSON for Modern C++ (supporting code)
+// |  |  |__   |  |  | | | |  version 3.12.0
+// |_____|_____|_____|_|___|  https://github.com/nlohmann/json
+//
+// SPDX-FileCopyrightText: 2013-2026 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);
+            }
+        }
+    }
+}