json/test/value_to.cpp

//
// Copyright (c) 2019 Vinnie Falco (vinnie.falco@gmail.com)
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//
// Official repository: https://github.com/boostorg/json
//

// Test that header file is self-contained.
#include <boost/json/value_to.hpp>

#include "test_suite.hpp"

#include <array>
#include <map>
#include <unordered_map>
#include <vector>

namespace value_to_test_ns
{

struct T1 { };

} // namespace value_to_test_ns

BOOST_JSON_NS_BEGIN

template<>
struct is_null_like<::value_to_test_ns::T1> : std::true_type { };

template <class T, class = void>
struct can_apply_value_to
    : std::false_type
{
};

template <class T>
struct can_apply_value_to<T, detail::void_t<decltype(
    value_to<int>(std::declval<T>()))
>>
    : std::true_type
{
};

BOOST_STATIC_ASSERT(!can_apply_value_to<int>::value);

class value_to_test
{
public:

    template<class T>
    void
    check(T t)
    {
        BOOST_TEST(value_to<T>(value_from(t)) == t);
    }

    void
    testNumberCast()
    {
        check((short)-1);
        check((int)-2);
        check((long)-3);
        check((long long)-4);
        check((unsigned short)1);
        check((unsigned int)2);
        check((unsigned long)3);
        check((unsigned long long)4);
        check((float)1.5);
        check((double)2.5);
        check(true);
    }

    void
    testJsonTypes()
    {
        value_to<object>(value(object_kind));
        value_to<array>(value(array_kind));
        value_to<string>(value(string_kind));
    }

    void
    testGenerics()
    {
        check(std::string("test"));
        check(std::map<std::string, int>
        {
            {"a", 1}, {"b", 2}, {"c", 3}
        });
        check(std::multimap<std::string, int>
        {
            {"2", 4}, {"3", 9}, {"5", 25}
        });
        check(std::unordered_map<std::string, int>
        {
            { "a", 1 }, {"b", 2}, {"c", 3}
        });
        check(std::vector<int>{1, 2, 3, 4});
        check(std::make_pair(std::string("test"), 5));
        check(std::make_tuple(std::string("outer"),
            std::make_pair(std::string("test"), 5)));
        check(std::map<int, int>
        {
            {2, 4}, {3, 9}, {5, 25}
        });

        {
            std::array<int, 1000> arr;
            arr.fill(0);
            check(arr);
        }

        BOOST_TEST_THROWS(
            (value_to<std::tuple<int, int>>(value{1, 2, 3})),
            std::invalid_argument);
        BOOST_TEST_THROWS(
            (value_to<std::tuple<int, int, int, int>>(value{1, 2, 3})),
            std::invalid_argument);

        BOOST_TEST_THROWS(
            (value_to<std::array<int, 4>>(value{1, 2, 3})),
            std::invalid_argument);
        BOOST_TEST_THROWS(
            (value_to<std::array<int, 4>>(value{1, 2, 3, 4, 5})),
            std::invalid_argument);
    }

    void
    testContainerHelpers()
    {
        {
            std::vector<int> v;
            detail::try_reserve(
                v, 10, detail::reserve_implementation<decltype(v)>());
            BOOST_TEST(v.capacity() >= 10);
            BOOST_STATIC_ASSERT(std::is_same<
                decltype(detail::inserter(
                    v, detail::inserter_implementation<decltype(v)>())),
                decltype(std::back_inserter(v)) >::value);
        }
        {
            std::array<int, 2> arr;
            detail::try_reserve(
                arr, 2, detail::reserve_implementation<decltype(arr)>());
        }
        {
            int n;
            detail::try_reserve(
                n, 5, detail::reserve_implementation<decltype(n)>());
        }
    }

    void testNullptr()
    {
        (void)value_to<std::nullptr_t>(value());
        (void)value_to<::value_to_test_ns::T1>(value());
        BOOST_TEST_THROWS(
            (value_to<std::nullptr_t>(value(1))), std::invalid_argument);
        BOOST_TEST_THROWS(
            (value_to<::value_to_test_ns::T1>(value(1))),
            std::invalid_argument);
    }

    void
    run()
    {
        testNumberCast();
        testJsonTypes();
        testGenerics();
        testContainerHelpers();
        testNullptr();
    }
};

TEST_SUITE(value_to_test, "boost.json.value_to");

BOOST_JSON_NS_END