[C] List Traversal with map function

bool test_list_map()
{
    // Nested function, available in GCC.
    int square(int n)
    {
        return n * n;
    }

    bool failed = false;

    // List p: 1 -> 2 -> 3 -> NULL
    List *lp = list_init(3, 1, 2, 3);
    if (lp == NULL) {
        perror("Failed to allocate List lp");
        return false;
    }

    // List q: 1 -> 4 -> 9 -> NULL
    // Traverse in functional style.
    List *lq = list_map(lp, square);
    if (lq == NULL) {
        perror("Failed to allocate List lq");
        failed = true;
        goto LIST_P_FREE;
    }

    int arr[] = {1, 4, 9};
    size_t i = 0;
    for (Node *it = list_start(lq); !list_end(it); it = list_next(it)) {
        if (node_value(it) != arr[i]) {
            failed = true;
            goto LIST_Q_FREE;
        }

        i++;
    }

LIST_Q_FREE:
    list_free(lq);
LIST_P_FREE:
    list_free(lp);

    if (failed) {
        return false;
    }

    return true;
}