random_tests.cpp

// Copyright (c) 2017 The Bitcoin Core developers
// Copyright (c) 2017-2021 The Raven Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#include "random.h"

#include "test/test_raven.h"

#include <boost/test/unit_test.hpp>

BOOST_FIXTURE_TEST_SUITE(random_tests, BasicTestingSetup)

    BOOST_AUTO_TEST_CASE(osrandom_test)
    {
        BOOST_TEST_MESSAGE("Running OSrandom Test");
        BOOST_CHECK(Random_SanityCheck());
    }

    BOOST_AUTO_TEST_CASE(fastrandom_test)
    {
        BOOST_TEST_MESSAGE("Running FastRandom Test");

        // Check that deterministic FastRandomContexts are deterministic
        FastRandomContext ctx1(true);
        FastRandomContext ctx2(true);

        BOOST_CHECK_EQUAL(ctx1.rand32(), ctx2.rand32());
        BOOST_CHECK_EQUAL(ctx1.rand32(), ctx2.rand32());
        BOOST_CHECK_EQUAL(ctx1.rand64(), ctx2.rand64());
        BOOST_CHECK_EQUAL(ctx1.randbits(3), ctx2.randbits(3));
        BOOST_CHECK(ctx1.randbytes(17) == ctx2.randbytes(17));
        BOOST_CHECK(ctx1.rand256() == ctx2.rand256());
        BOOST_CHECK_EQUAL(ctx1.randbits(7), ctx2.randbits(7));
        BOOST_CHECK(ctx1.randbytes(128) == ctx2.randbytes(128));
        BOOST_CHECK_EQUAL(ctx1.rand32(), ctx2.rand32());
        BOOST_CHECK_EQUAL(ctx1.randbits(3), ctx2.randbits(3));
        BOOST_CHECK(ctx1.rand256() == ctx2.rand256());
        BOOST_CHECK(ctx1.randbytes(50) == ctx2.randbytes(50));

        // Check that a nondeterministic ones are not
        FastRandomContext ctx3;
        FastRandomContext ctx4;
        BOOST_CHECK(ctx3.rand64() != ctx4.rand64()); // extremely unlikely to be equal
        BOOST_CHECK(ctx3.rand256() != ctx4.rand256());
        BOOST_CHECK(ctx3.randbytes(7) != ctx4.randbytes(7));
    }

    BOOST_AUTO_TEST_CASE(fastrandom_randbits_test)
    {
        BOOST_TEST_MESSAGE("Running FastRandom RandBits Test");

        FastRandomContext ctx1;
        FastRandomContext ctx2;
        for (int bits = 0; bits < 63; ++bits)
        {
            for (int j = 0; j < 1000; ++j)
            {
                uint64_t rangebits = ctx1.randbits(bits);
                BOOST_CHECK_EQUAL(rangebits >> bits, (uint64_t)0);
                uint64_t range = ((uint64_t) 1) << bits | rangebits;
                uint64_t rand = ctx2.randrange(range);
                BOOST_CHECK(rand < range);
            }
        }
    }

    /** Test that Shuffle reaches every permutation with equal probability. */
    BOOST_AUTO_TEST_CASE(shuffle_stat_test)
    {
        FastRandomContext ctx(true);
        uint32_t counts[5 * 5 * 5 * 5 * 5] = {0};
        for (int i = 0; i < 12000; ++i) {
            int data[5] = {0, 1, 2, 3, 4};
            Shuffle(std::begin(data), std::end(data), ctx);
            int pos = data[0] + data[1] * 5 + data[2] * 25 + data[3] * 125 + data[4] * 625;
            ++counts[pos];
        }
        unsigned int sum = 0;
        double chi_score = 0.0;
        for (int i = 0; i < 5 * 5 * 5 * 5 * 5; ++i) {
            int i1 = i % 5, i2 = (i / 5) % 5, i3 = (i / 25) % 5, i4 = (i / 125) % 5, i5 = i / 625;
            uint32_t count = counts[i];
            if (i1 == i2 || i1 == i3 || i1 == i4 || i1 == i5 || i2 == i3 || i2 == i4 || i2 == i5 || i3 == i4 || i3 == i5 || i4 == i5) {
                BOOST_CHECK(count == 0);
        } else {
            chi_score += ((count - 100.0) * (count - 100.0)) / 100.0;
            BOOST_CHECK(count > 50);
            BOOST_CHECK(count < 150);
            sum += count;
        }
    }
    BOOST_CHECK(chi_score > 58.1411); // 99.9999% confidence interval
    BOOST_CHECK(chi_score < 210.275);
    BOOST_CHECK_EQUAL(sum, 12000);
}

BOOST_AUTO_TEST_SUITE_END()