Function TestIterPartial

util/random/shuffle_ut.cpp:49–80

    template <typename... A>
    static void TestIterPartial(A&&... args) {
        TString s0, s1;

        auto f = [&](int shuffledSize) {
            auto b = s1.begin();
            auto e = s1.end();

            PartialShuffle(b, e, shuffledSize, args...);
        };

        s1 = "";
        f(0);

        s1 = "01";
        f(1);

        s1 = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ,.;?!";
        s0 = s1.copy();
        f(2);
        size_t matchesCount = 0;
        for (size_t i = 0; i < s0.size(); ++i) {
            matchesCount += (s0[i] == s1[i]);
        }

        UNIT_ASSERT(matchesCount >= s1.size() - 4); // partial shuffle doesn't make non-necessary swaps.

        s1 = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ,.;?!";
        s0 = s1.copy();
        f(64);

        UNIT_ASSERT(s0 != s1); // if partial shuffle does work, chances it will fail are 1 to 64!.
    }

    Y_UNIT_TEST(TestShuffle) {
        TestRange();