TEST_CASE("find_one_and_update works with unacknowledged write concern", "[collection]") {
    instance::current();
    mongocxx::client client{uri{}, test_util::add_test_server_api()};
    mongocxx::write_concern wc;
    wc.acknowledge_level(mongocxx::write_concern::level::k_unacknowledged);

    auto collection = client["fam_wc"]["collection"];
    collection.drop();
    collection.insert_one(make_document(kvp("x", 1)));

    stdx::optional<bsoncxx::document::value> doc;
    mongocxx::options::find_one_and_update find_one_and_update_opts;
    find_one_and_update_opts.write_concern(wc);
    // find_one_and_update gets an exception with message:
    // "cannot return the type of uninitialized element: unset document::element"
    doc = collection.find_one_and_update(
        {}, make_document(kvp("$set", make_document(kvp("x", 2)))), find_one_and_update_opts);
    REQUIRE(!doc);
}