boost/libs/unordered/test/unordered/noexcept_tests.cpp

// Copyright 2013 Daniel James.
// 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)

#include "../helpers/prefix.hpp"
#include <boost/unordered_set.hpp>
#include <boost/unordered_map.hpp>
#include "../helpers/postfix.hpp"

#include "../helpers/test.hpp"

namespace noexcept_tests
{
    // Test the noexcept is set correctly for the move constructor.
 
    struct hash_possible_exception : boost::hash<int>
    {
        hash_possible_exception(hash_possible_exception const&) {}
    };

    struct equal_to_possible_exception : std::equal_to<int>
    {
        equal_to_possible_exception(equal_to_possible_exception const&) {}
    };

    UNORDERED_AUTO_TEST(test_noexcept)
    {
#if !defined(BOOST_NO_CXX11_NOEXCEPT)
        BOOST_TEST((boost::is_nothrow_move_constructible<
                    boost::unordered_set<int> >::value));
        BOOST_TEST((boost::is_nothrow_move_constructible<
                    boost::unordered_multiset<int> >::value));
        BOOST_TEST((boost::is_nothrow_move_constructible<
                    boost::unordered_map<int, int> >::value));
        BOOST_TEST((boost::is_nothrow_move_constructible<
                    boost::unordered_multimap<int, int> >::value));
#endif

        BOOST_TEST((!boost::is_nothrow_move_constructible<
                    boost::unordered_set<int, hash_possible_exception>
                >::value));
        BOOST_TEST((!boost::is_nothrow_move_constructible<
                    boost::unordered_multiset<int, boost::hash<int>,
                    equal_to_possible_exception>
                >::value));
    }

    // Test that the move constructor does actually move without throwing
    // an exception when it claims to.

    struct test_exception {};

    bool throwing_test_exception = false;
    void test_throw(char const* name) {
        if (throwing_test_exception) {
            std::cerr << "Throw exception in: " << name << std::endl;
            throw test_exception();
        }
    }

    class hash_nothrow_move : boost::hash<int>
    {
        BOOST_COPYABLE_AND_MOVABLE(hash_nothrow_move)

        typedef boost::hash<int> base;
    public:
        hash_nothrow_move(BOOST_RV_REF(hash_nothrow_move))
            BOOST_NOEXCEPT {}

        hash_nothrow_move() { test_throw("Constructor"); }
        hash_nothrow_move(hash_nothrow_move const&) { test_throw("Copy"); }
        hash_nothrow_move& operator=(hash_nothrow_move const&)
        { test_throw("Assign"); return *this; }
        std::size_t operator()(int x) const
        { test_throw("Operator"); return static_cast<base const&>(*this)(x); }
    };

    class equal_to_nothrow_move : std::equal_to<int>
    {
        BOOST_COPYABLE_AND_MOVABLE(equal_to_nothrow_move)

        typedef std::equal_to<int> base;
    public:
        equal_to_nothrow_move(BOOST_RV_REF(equal_to_nothrow_move))
            BOOST_NOEXCEPT {}
        equal_to_nothrow_move() { test_throw("Constructor"); }
        equal_to_nothrow_move(equal_to_nothrow_move const&)
        { test_throw("Copy"); }
        equal_to_nothrow_move& operator=(equal_to_nothrow_move const&)
        { test_throw("Assign"); return *this; }
        std::size_t operator()(int x, int y) const
        { test_throw("Operator"); return static_cast<base const&>(*this)(x, y); }
    };

    UNORDERED_AUTO_TEST(test_no_throw_when_noexcept)
    {
        typedef boost::unordered_set<int,
                hash_nothrow_move, equal_to_nothrow_move> throwing_set;

        if (boost::is_nothrow_move_constructible<throwing_set>::value)
        {
            throwing_test_exception = false;

            throwing_set x1;
            x1.insert(10);
            x1.insert(50);


            try {
                throwing_test_exception = true;

                throwing_set x2 = boost::move(x1);
                BOOST_TEST(x2.size() == 2);
                BOOST_TEST(*x2.begin() == 10 || *x2.begin() == 50);
            } catch(test_exception) {
                BOOST_TEST(false);
            }

            throwing_test_exception = false;
        }
    }
}

RUN_TESTS()