CasheLifeTime

using namespace std;
struct ObjectFactory2 {

    int count = 0;

    ObjectFactory2(int count) : count(count) {
    }

    ObjectFactory2() = default;

    ObjectPtr operator()(std::string id) {
        id += "_"s + to_string(count);
        ++count;
        return std::make_shared<Object>(std::move(id));
    }
};
void CacheTest() {
    using namespace std;
    weak_ptr<Object> bob_wp;
    {
        Cache<string, Object, ObjectFactory2> cache;

        auto alice1 = cache.GetValue("Alice"s);
        auto bob = cache.GetValue("Bob"s);

        auto alice2 = cache.GetValue("Alice"s);
        assert(alice1== alice2);

        weak_ptr alice_wp{ alice1 };
        bob_wp = bob;
        assert(!alice_wp.expired());
        assert(!bob_wp.expired());

        alice1.reset();
        assert(!alice_wp.expired());

        alice2.reset();
        assert(alice_wp.expired());
    }
    assert(bob_wp.expired());
}