tests/src/unit-readme.cpp - third_party/json - Git at Google

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

 #include "doctest_compatibility.h"

 #include <nlohmann/json.hpp>
 using nlohmann::json;
 #ifdef JSON_TEST_NO_GLOBAL_UDLS
     using namespace nlohmann::literals; // NOLINT(google-build-using-namespace)
 #endif

 #include <deque>
 #include <forward_list>
 #include <list>
 #include <set>
 #include <unordered_map>
 #include <unordered_set>
 #include <iostream>
 #include <sstream>
 #include <iomanip>

 // local variable is initialized but not referenced
 DOCTEST_MSVC_SUPPRESS_WARNING_PUSH
 DOCTEST_MSVC_SUPPRESS_WARNING(4189)

 TEST_CASE("README" * doctest::skip())
 {
     {
         // redirect std::cout for the README file
         auto* old_cout_buffer = std::cout.rdbuf();
         std::ostringstream const new_stream;
         std::cout.rdbuf(new_stream.rdbuf());
         {
             // create an empty structure (null)
             json j;

             // add a number that is stored as double (note the implicit conversion of j to an object)
             j["pi"] = 3.141;

             // add a Boolean that is stored as bool
             j["happy"] = true;

             // add a string that is stored as std::string
             j["name"] = "Niels";

             // add another null object by passing nullptr
             j["nothing"] = nullptr;

             // add an object inside the object
             j["answer"]["everything"] = 42;

             // add an array that is stored as std::vector (using an initializer list)
             j["list"] = { 1, 0, 2 };

             // add another object (using an initializer list of pairs)
             j["object"] = { {"currency", "USD"}, {"value", 42.99} };

             // instead, you could also write (which looks very similar to the JSON above)
             json const j2 =
             {
                 {"pi", 3.141},
                 {"happy", true},
                 {"name", "Niels"},
                 {"nothing", nullptr},
                 {
                     "answer", {
                         {"everything", 42}
                     }
                 },
                 {"list", {1, 0, 2}},
                 {
                     "object", {
                         {"currency", "USD"},
                         {"value", 42.99}
                     }
                 }
             };
         }

         {
             // ways to express the empty array []
             json const empty_array_implicit = {{}};
             CHECK(empty_array_implicit.is_array());
             json const empty_array_explicit = json::array();
             CHECK(empty_array_explicit.is_array());

             // a way to express the empty object {}
             json const empty_object_explicit = json::object();
             CHECK(empty_object_explicit.is_object());

             // a way to express an _array_ of key/value pairs [["currency", "USD"], ["value", 42.99]]
             json array_not_object = json::array({ {"currency", "USD"}, {"value", 42.99} });
             CHECK(array_not_object.is_array());
             CHECK(array_not_object.size() == 2);
             CHECK(array_not_object[0].is_array());
             CHECK(array_not_object[1].is_array());
         }

         {
             // create object from string literal
             json const j = "{ \"happy\": true, \"pi\": 3.141 }"_json; // NOLINT(modernize-raw-string-literal)

             // or even nicer with a raw string literal
             auto j2 = R"({
                 "happy": true,
                 "pi": 3.141
             })"_json;

             // or explicitly
             auto j3 = json::parse(R"({"happy": true, "pi": 3.141})");

             // explicit conversion to string
             std::string const s = j.dump();    // {\"happy\":true,\"pi\":3.141}

             // serialization with pretty printing
             // pass in the amount of spaces to indent
             std::cout << j.dump(4) << std::endl; // NOLINT(performance-avoid-endl)
             // {
             //     "happy": true,
             //     "pi": 3.141
             // }

             std::cout << std::setw(2) << j << std::endl; // NOLINT(performance-avoid-endl)
         }

         {
             // create an array using push_back
             json j;
             j.push_back("foo");
             j.push_back(1);
             j.push_back(true);

             // comparison
             bool x = (j == R"(["foo", 1, true])"_json);  // true
             CHECK(x == true);

             // iterate the array
             for (json::iterator it = j.begin(); it != j.end(); ++it) // NOLINT(modernize-loop-convert)
             {
                 std::cout << *it << '\n';
             }

             // range-based for
             for (auto& element : j)
             {
                 std::cout << element << '\n';
             }

             // getter/setter
             const auto tmp = j[0].get<std::string>();
             j[1] = 42;
             bool foo{j.at(2)};
             CHECK(foo == true);

             // other stuff
             CHECK(j.size() == 3);                     // 3 entries
             CHECK_FALSE(j.empty());                   // false
             CHECK(j.type() == json::value_t::array);  // json::value_t::array
             j.clear();                                // the array is empty again

             // create an object
             json o;
             o["foo"] = 23;
             o["bar"] = false;
             o["baz"] = 3.141;

             // find an entry
             CHECK(o.find("foo") != o.end());
             if (o.find("foo") != o.end())
             {
                 // there is an entry with key "foo"
             }
         }

         {
             std::vector<int> const c_vector {1, 2, 3, 4};
             json const j_vec(c_vector);
             // [1, 2, 3, 4]

             std::deque<float> const c_deque {1.2f, 2.3f, 3.4f, 5.6f};
             json const j_deque(c_deque);
             // [1.2, 2.3, 3.4, 5.6]

             std::list<bool> const c_list {true, true, false, true};
             json const j_list(c_list);
             // [true, true, false, true]

             std::forward_list<int64_t> const c_flist {12345678909876, 23456789098765, 34567890987654, 45678909876543};
             json const j_flist(c_flist);
             // [12345678909876, 23456789098765, 34567890987654, 45678909876543]

             std::array<unsigned long, 4> const c_array {{1, 2, 3, 4}};
             json const j_array(c_array);
             // [1, 2, 3, 4]

             std::set<std::string> const c_set {"one", "two", "three", "four", "one"};
             json const j_set(c_set); // only one entry for "one" is used
             // ["four", "one", "three", "two"]

             std::unordered_set<std::string> const c_uset {"one", "two", "three", "four", "one"};
             json const j_uset(c_uset); // only one entry for "one" is used
             // maybe ["two", "three", "four", "one"]

             std::multiset<std::string> const c_mset {"one", "two", "one", "four"};
             json const j_mset(c_mset); // both entries for "one" are used
             // maybe ["one", "two", "one", "four"]

             std::unordered_multiset<std::string> const c_umset {"one", "two", "one", "four"};
             json const j_umset(c_umset); // both entries for "one" are used
             // maybe ["one", "two", "one", "four"]
         }

         {
             std::map<std::string, int> const c_map { {"one", 1}, {"two", 2}, {"three", 3} };
             json const j_map(c_map);
             // {"one": 1, "two": 2, "three": 3}

             std::unordered_map<const char*, float> const c_umap { {"one", 1.2f}, {"two", 2.3f}, {"three", 3.4f} };
             json const j_umap(c_umap);
             // {"one": 1.2, "two": 2.3, "three": 3.4}

             std::multimap<std::string, bool> const c_mmap { {"one", true}, {"two", true}, {"three", false}, {"three", true} };
             json const j_mmap(c_mmap); // only one entry for key "three" is used
             // maybe {"one": true, "two": true, "three": true}

             std::unordered_multimap<std::string, bool> const c_ummap { {"one", true}, {"two", true}, {"three", false}, {"three", true} };
             json const j_ummap(c_ummap); // only one entry for key "three" is used
             // maybe {"one": true, "two": true, "three": true}
         }

         {
             // strings
             std::string const s1 = "Hello, world!";
             json const js = s1;
             auto s2 = js.get<std::string>();

             // Booleans
             bool const b1 = true;
             json const jb = b1;
             bool b2{jb};
             CHECK(b2 == true);

             // numbers
             int const i = 42;
             json const jn = i;
             double f{jn};
             CHECK(f == 42);

             // etc.

             std::string const vs = js.get<std::string>();
             bool vb = jb.get<bool>();
             CHECK(vb == true);
             int vi = jn.get<int>();
             CHECK(vi == 42);

             // etc.
         }

         {
             // a JSON value
             json j_original = R"({
                 "baz": ["one", "two", "three"],
                 "foo": "bar"
             })"_json;

             // access members with a JSON pointer (RFC 6901)
             j_original["/baz/1"_json_pointer];
             // "two"

             // a JSON patch (RFC 6902)
             json const j_patch = R"([
                 { "op": "replace", "path": "/baz", "value": "boo" },
                 { "op": "add", "path": "/hello", "value": ["world"] },
                 { "op": "remove", "path": "/foo"}
             ])"_json;

             // apply the patch
             json const j_result = j_original.patch(j_patch);
             // {
             //    "baz": "boo",
             //    "hello": ["world"]
             // }

             // calculate a JSON patch from two JSON values
             auto res = json::diff(j_result, j_original);
             // [
             //   { "op":" replace", "path": "/baz", "value": ["one", "two", "three"] },
             //   { "op":"remove","path":"/hello" },
             //   { "op":"add","path":"/foo","value":"bar" }
             // ]
         }

         // restore old std::cout
         std::cout.rdbuf(old_cout_buffer);
     }
 }

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

	#include "doctest_compatibility.h"

	#include <nlohmann/json.hpp>
	using nlohmann::json;
	#ifdef JSON_TEST_NO_GLOBAL_UDLS
	using namespace nlohmann::literals; // NOLINT(google-build-using-namespace)
	#endif

	#include <deque>
	#include <forward_list>
	#include <list>
	#include <set>
	#include <unordered_map>
	#include <unordered_set>
	#include <iostream>
	#include <sstream>
	#include <iomanip>

	// local variable is initialized but not referenced
	DOCTEST_MSVC_SUPPRESS_WARNING_PUSH
	DOCTEST_MSVC_SUPPRESS_WARNING(4189)

	TEST_CASE("README" * doctest::skip())
	{
	{
	// redirect std::cout for the README file
	auto* old_cout_buffer = std::cout.rdbuf();
	std::ostringstream const new_stream;
	std::cout.rdbuf(new_stream.rdbuf());
	{
	// create an empty structure (null)
	json j;

	// add a number that is stored as double (note the implicit conversion of j to an object)
	j["pi"] = 3.141;

	// add a Boolean that is stored as bool
	j["happy"] = true;

	// add a string that is stored as std::string
	j["name"] = "Niels";

	// add another null object by passing nullptr
	j["nothing"] = nullptr;

	// add an object inside the object
	j["answer"]["everything"] = 42;

	// add an array that is stored as std::vector (using an initializer list)
	j["list"] = { 1, 0, 2 };

	// add another object (using an initializer list of pairs)
	j["object"] = { {"currency", "USD"}, {"value", 42.99} };

	// instead, you could also write (which looks very similar to the JSON above)
	json const j2 =
	{
	{"pi", 3.141},
	{"happy", true},
	{"name", "Niels"},
	{"nothing", nullptr},
	{
	"answer", {
	{"everything", 42}
	}
	},
	{"list", {1, 0, 2}},
	{
	"object", {
	{"currency", "USD"},
	{"value", 42.99}
	}
	}
	};
	}

	{
	// ways to express the empty array []
	json const empty_array_implicit = {{}};
	CHECK(empty_array_implicit.is_array());
	json const empty_array_explicit = json::array();
	CHECK(empty_array_explicit.is_array());

	// a way to express the empty object {}
	json const empty_object_explicit = json::object();
	CHECK(empty_object_explicit.is_object());

	// a way to express an _array_ of key/value pairs [["currency", "USD"], ["value", 42.99]]
	json array_not_object = json::array({ {"currency", "USD"}, {"value", 42.99} });
	CHECK(array_not_object.is_array());
	CHECK(array_not_object.size() == 2);
	CHECK(array_not_object[0].is_array());
	CHECK(array_not_object[1].is_array());
	}

	{
	// create object from string literal
	json const j = "{ \"happy\": true, \"pi\": 3.141 }"_json; // NOLINT(modernize-raw-string-literal)

	// or even nicer with a raw string literal
	auto j2 = R"({
	"happy": true,
	"pi": 3.141
	})"_json;

	// or explicitly
	auto j3 = json::parse(R"({"happy": true, "pi": 3.141})");

	// explicit conversion to string
	std::string const s = j.dump(); // {\"happy\":true,\"pi\":3.141}

	// serialization with pretty printing
	// pass in the amount of spaces to indent
	std::cout << j.dump(4) << std::endl; // NOLINT(performance-avoid-endl)
	// {
	// "happy": true,
	// "pi": 3.141
	// }

	std::cout << std::setw(2) << j << std::endl; // NOLINT(performance-avoid-endl)
	}

	{
	// create an array using push_back
	json j;
	j.push_back("foo");
	j.push_back(1);
	j.push_back(true);

	// comparison
	bool x = (j == R"(["foo", 1, true])"_json); // true
	CHECK(x == true);

	// iterate the array
	for (json::iterator it = j.begin(); it != j.end(); ++it) // NOLINT(modernize-loop-convert)
	{
	std::cout << *it << '\n';
	}

	// range-based for
	for (auto& element : j)
	{
	std::cout << element << '\n';
	}

	// getter/setter
	const auto tmp = j[0].get<std::string>();
	j[1] = 42;
	bool foo{j.at(2)};
	CHECK(foo == true);

	// other stuff
	CHECK(j.size() == 3); // 3 entries
	CHECK_FALSE(j.empty()); // false
	CHECK(j.type() == json::value_t::array); // json::value_t::array
	j.clear(); // the array is empty again

	// create an object
	json o;
	o["foo"] = 23;
	o["bar"] = false;
	o["baz"] = 3.141;

	// find an entry
	CHECK(o.find("foo") != o.end());
	if (o.find("foo") != o.end())
	{
	// there is an entry with key "foo"
	}
	}

	{
	std::vector<int> const c_vector {1, 2, 3, 4};
	json const j_vec(c_vector);
	// [1, 2, 3, 4]

	std::deque<float> const c_deque {1.2f, 2.3f, 3.4f, 5.6f};
	json const j_deque(c_deque);
	// [1.2, 2.3, 3.4, 5.6]

	std::list<bool> const c_list {true, true, false, true};
	json const j_list(c_list);
	// [true, true, false, true]

	std::forward_list<int64_t> const c_flist {12345678909876, 23456789098765, 34567890987654, 45678909876543};
	json const j_flist(c_flist);
	// [12345678909876, 23456789098765, 34567890987654, 45678909876543]

	std::array<unsigned long, 4> const c_array {{1, 2, 3, 4}};
	json const j_array(c_array);
	// [1, 2, 3, 4]

	std::set<std::string> const c_set {"one", "two", "three", "four", "one"};
	json const j_set(c_set); // only one entry for "one" is used
	// ["four", "one", "three", "two"]

	std::unordered_set<std::string> const c_uset {"one", "two", "three", "four", "one"};
	json const j_uset(c_uset); // only one entry for "one" is used
	// maybe ["two", "three", "four", "one"]

	std::multiset<std::string> const c_mset {"one", "two", "one", "four"};
	json const j_mset(c_mset); // both entries for "one" are used
	// maybe ["one", "two", "one", "four"]

	std::unordered_multiset<std::string> const c_umset {"one", "two", "one", "four"};
	json const j_umset(c_umset); // both entries for "one" are used
	// maybe ["one", "two", "one", "four"]
	}

	{
	std::map<std::string, int> const c_map { {"one", 1}, {"two", 2}, {"three", 3} };
	json const j_map(c_map);
	// {"one": 1, "two": 2, "three": 3}

	std::unordered_map<const char*, float> const c_umap { {"one", 1.2f}, {"two", 2.3f}, {"three", 3.4f} };
	json const j_umap(c_umap);
	// {"one": 1.2, "two": 2.3, "three": 3.4}

	std::multimap<std::string, bool> const c_mmap { {"one", true}, {"two", true}, {"three", false}, {"three", true} };
	json const j_mmap(c_mmap); // only one entry for key "three" is used
	// maybe {"one": true, "two": true, "three": true}

	std::unordered_multimap<std::string, bool> const c_ummap { {"one", true}, {"two", true}, {"three", false}, {"three", true} };
	json const j_ummap(c_ummap); // only one entry for key "three" is used
	// maybe {"one": true, "two": true, "three": true}
	}

	{
	// strings
	std::string const s1 = "Hello, world!";
	json const js = s1;
	auto s2 = js.get<std::string>();

	// Booleans
	bool const b1 = true;
	json const jb = b1;
	bool b2{jb};
	CHECK(b2 == true);

	// numbers
	int const i = 42;
	json const jn = i;
	double f{jn};
	CHECK(f == 42);

	// etc.

	std::string const vs = js.get<std::string>();
	bool vb = jb.get<bool>();
	CHECK(vb == true);
	int vi = jn.get<int>();
	CHECK(vi == 42);

	// etc.
	}

	{
	// a JSON value
	json j_original = R"({
	"baz": ["one", "two", "three"],
	"foo": "bar"
	})"_json;

	// access members with a JSON pointer (RFC 6901)
	j_original["/baz/1"_json_pointer];
	// "two"

	// a JSON patch (RFC 6902)
	json const j_patch = R"([
	{ "op": "replace", "path": "/baz", "value": "boo" },
	{ "op": "add", "path": "/hello", "value": ["world"] },
	{ "op": "remove", "path": "/foo"}
	])"_json;

	// apply the patch
	json const j_result = j_original.patch(j_patch);
	// {
	// "baz": "boo",
	// "hello": ["world"]
	// }

	// calculate a JSON patch from two JSON values
	auto res = json::diff(j_result, j_original);
	// [
	// { "op":" replace", "path": "/baz", "value": ["one", "two", "three"] },
	// { "op":"remove","path":"/hello" },
	// { "op":"add","path":"/foo","value":"bar" }
	// ]
	}

	// restore old std::cout
	std::cout.rdbuf(old_cout_buffer);
	}
	}

	DOCTEST_MSVC_SUPPRESS_WARNING_POP