Set<List<Integer>> degenerate = cartesianProduct();
    checkHashCode(degenerate);

    checkHashCode(cartesianProduct(set(1, 2)));

    int num = Integer.MAX_VALUE / 3 * 2; // tickle overflow-related problems
    checkHashCode(cartesianProduct(set(1, 2, num)));

    Set<Integer> mt = emptySet();
    checkHashCode(cartesianProduct(mt, mt));
    checkHashCode(cartesianProduct(mt, set(num)));