json/tests/src/unit-comparison.cpp

/*
    __ _____ _____ _____
 __|  |   __|     |   | |  JSON for Modern C++ (test suite)
|  |  |__   |  |  | | | |  version 3.10.5
|_____|_____|_____|_|___|  https://github.com/nlohmann/json

Licensed under the MIT License <http://opensource.org/licenses/MIT>.
SPDX-License-Identifier: MIT
Copyright (c) 2013-2022 Niels Lohmann <http://nlohmann.me>.

Permission is hereby  granted, free of charge, to any  person obtaining a copy
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THE SOFTWARE  IS PROVIDED "AS  IS", WITHOUT WARRANTY  OF ANY KIND,  EXPRESS OR
IMPLIED,  INCLUDING BUT  NOT  LIMITED TO  THE  WARRANTIES OF  MERCHANTABILITY,
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*/

#include "doctest_compatibility.h"

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

namespace
{
// helper function to check std::less<json::value_t>
// see https://en.cppreference.com/w/cpp/utility/functional/less
template <typename A, typename B, typename U = std::less<json::value_t>>
bool f(A a, B b, U u = U())
{
    return u(a, b);
}
} // namespace

TEST_CASE("lexicographical comparison operators")
{
    SECTION("types")
    {
        std::vector<json::value_t> j_types =
        {
            json::value_t::null,
            json::value_t::boolean,
            json::value_t::number_integer,
            json::value_t::number_unsigned,
            json::value_t::number_float,
            json::value_t::object,
            json::value_t::array,
            json::value_t::string,
            json::value_t::binary
        };

        SECTION("comparison: less")
        {
            std::vector<std::vector<bool>> expected =
            {
                {false, true, true, true, true, true, true, true, true},
                {false, false, true, true, true, true, true, true, true},
                {false, false, false, false, false, true, true, true, true},
                {false, false, false, false, false, true, true, true, true},
                {false, false, false, false, false, true, true, true, true},
                {false, false, false, false, false, false, true, true, true},
                {false, false, false, false, false, false, false, true, true},
                {false, false, false, false, false, false, false, false, true},
                {false, false, false, false, false, false, false, false, false}
            };

            for (size_t i = 0; i < j_types.size(); ++i)
            {
                for (size_t j = 0; j < j_types.size(); ++j)
                {
                    CAPTURE(i)
                    CAPTURE(j)
                    // check precomputed values
                    CHECK(operator<(j_types[i], j_types[j]) == expected[i][j]);
                    CHECK(f(j_types[i], j_types[j]) == expected[i][j]);
                }
            }
        }
    }

    SECTION("values")
    {
        json j_values =
        {
            nullptr, nullptr,
            -17, 42,
            8u, 13u,
            3.14159, 23.42,
            "foo", "bar",
            true, false,
            {1, 2, 3}, {"one", "two", "three"},
            {{"first", 1}, {"second", 2}}, {{"a", "A"}, {"b", {"B"}}},
            json::binary({1, 2, 3}), json::binary({1, 2, 4})
        };

        SECTION("comparison: equal")
        {
            std::vector<std::vector<bool>> expected =
            {
                {true, true, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false},
                {true, true, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false},
                {false, false, true, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false},
                {false, false, false, true, false, false, false, false, false, false, false, false, false, false, false, false, false, false},
                {false, false, false, false, true, false, false, false, false, false, false, false, false, false, false, false, false, false},
                {false, false, false, false, false, true, false, false, false, false, false, false, false, false, false, false, false, false},
                {false, false, false, false, false, false, true, false, false, false, false, false, false, false, false, false, false, false},
                {false, false, false, false, false, false, false, true, false, false, false, false, false, false, false, false, false, false},
                {false, false, false, false, false, false, false, false, true, false, false, false, false, false, false, false, false, false},
                {false, false, false, false, false, false, false, false, false, true, false, false, false, false, false, false, false, false},
                {false, false, false, false, false, false, false, false, false, false, true, false, false, false, false, false, false, false},
                {false, false, false, false, false, false, false, false, false, false, false, true, false, false, false, false, false, false},
                {false, false, false, false, false, false, false, false, false, false, false, false, true, false, false, false, false, false},
                {false, false, false, false, false, false, false, false, false, false, false, false, false, true, false, false, false, false},
                {false, false, false, false, false, false, false, false, false, false, false, false, false, false, true, false, false, false},
                {false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, true, false, false},
                {false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, true, false},
                {false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, true}
            };

            for (size_t i = 0; i < j_values.size(); ++i)
            {
                for (size_t j = 0; j < j_values.size(); ++j)
                {
                    CAPTURE(i)
                    CAPTURE(j)
                    CAPTURE(j_values[i])
                    CAPTURE(j_values[j])
                    // check precomputed values
                    CHECK( (j_values[i] == j_values[j]) == expected[i][j] );
                }
            }

            // comparison with discarded elements
            json j_discarded(json::value_t::discarded);
            for (const auto& v : j_values)
            {
                CHECK( (v == j_discarded) == false);
                CHECK( (j_discarded == v) == false);
                CHECK( (j_discarded == j_discarded) == false);
            }

            // compare with null pointer
            json j_null;
            CHECK(j_null == nullptr);
            CHECK(nullptr == j_null);
        }

        SECTION("comparison: not equal")
        {
            for (size_t i = 0; i < j_values.size(); ++i)
            {
                for (size_t j = 0; j < j_values.size(); ++j)
                {
                    CAPTURE(i)
                    CAPTURE(j)
                    // check definition
                    CHECK( (j_values[i] != j_values[j]) == !(j_values[i] == j_values[j]) );
                }
            }

            // compare with null pointer
            json j_null;
            CHECK( (j_null != nullptr) == false);
            CHECK( (nullptr != j_null) == false);
            CHECK( (j_null != nullptr) == !(j_null == nullptr));
            CHECK( (nullptr != j_null) == !(nullptr == j_null));
        }

        SECTION("comparison: less")
        {
            std::vector<std::vector<bool>> expected =
            {
                {false, false, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true},
                {false, false, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true},
                {false, false, false, true, true, true, true, true, true, true, false, false, true, true, true, true, true, true},
                {false, false, false, false, false, false, false, false, true, true, false, false, true, true, true, true, true, true},
                {false, false, false, true, false, true, false, true, true, true, false, false, true, true, true, true, true, true},
                {false, false, false, true, false, false, false, true, true, true, false, false, true, true, true, true, true, true},
                {false, false, false, true, true, true, false, true, true, true, false, false, true, true, true, true, true, true},
                {false, false, false, true, false, false, false, false, true, true, false, false, true, true, true, true, true, true},
                {false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, true, true},
                {false, false, false, false, false, false, false, false, true, false, false, false, false, false, false, false, true, true},
                {false, false, true, true, true, true, true, true, true, true, false, false, true, true, true, true, true, true},
                {false, false, true, true, true, true, true, true, true, true, true, false, true, true, true, true, true, true},
                {false, false, false, false, false, false, false, false, true, true, false, false, false, true, false, false, true, true},
                {false, false, false, false, false, false, false, false, true, true, false, false, false, false, false, false, true, true},
                {false, false, false, false, false, false, false, false, true, true, false, false, true, true, false, false, true, true},
                {false, false, false, false, false, false, false, false, true, true, false, false, true, true, true, false, true, true},
                {false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, true},
                {false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false}
            };

            for (size_t i = 0; i < j_values.size(); ++i)
            {
                for (size_t j = 0; j < j_values.size(); ++j)
                {
                    // Skip comparing indicies 12 and 13, and 13 and 12 in C++20 pending fix
                    // See issue #3207
#if defined(JSON_HAS_CPP_20) || JSON_HAS_THREE_WAY_COMPARISON
                    if ((i == 12 && j == 13) || (i == 13 && j == 12))
                    {
                        continue;
                    }
#endif
                    CAPTURE(i)
                    CAPTURE(j)
                    CAPTURE(j_values[i])
                    CAPTURE(j_values[j])
                    // check precomputed values
                    CHECK( (j_values[i] < j_values[j]) == expected[i][j] );
                }
            }

            // comparison with discarded elements
            json j_discarded(json::value_t::discarded);
            for (size_t i = 0; i < j_values.size(); ++i)
            {
                CAPTURE(i)
                CHECK( (j_values[i] < j_discarded) == false);
                CHECK( (j_discarded < j_values[i]) == false);
                CHECK( (j_discarded < j_discarded) == false);
            }
        }

        SECTION("comparison: less than or equal equal")
        {
            for (size_t i = 0; i < j_values.size(); ++i)
            {
                for (size_t j = 0; j < j_values.size(); ++j)
                {
                    CAPTURE(i)
                    CAPTURE(j)
                    // check definition
                    CHECK( (j_values[i] <= j_values[j]) == !(j_values[j] < j_values[i]) );
                }
            }
        }

        SECTION("comparison: greater than")
        {
            for (size_t i = 0; i < j_values.size(); ++i)
            {
                for (size_t j = 0; j < j_values.size(); ++j)
                {
                    CAPTURE(i)
                    CAPTURE(j)
                    // check definition
                    CHECK( (j_values[i] > j_values[j]) == (j_values[j] < j_values[i]) );
                }
            }
        }

        SECTION("comparison: greater than or equal")
        {
            for (size_t i = 0; i < j_values.size(); ++i)
            {
                for (size_t j = 0; j < j_values.size(); ++j)
                {
                    CAPTURE(i)
                    CAPTURE(j)
                    // check definition
                    CHECK( (j_values[i] >= j_values[j]) == !(j_values[i] < j_values[j]) );
                }
            }
        }
    }
}