static void test_skip_char(void) {
        const char *string = "foo";
        const char *in = string;
        size_t n_in = strlen(string);

        c_shquote_skip_char(&in, &n_in);
        c_assert(in == string + 1);
        c_assert(n_in == strlen(string) - 1);

        c_shquote_skip_char(&in, &n_in);
        c_assert(in == string + 2);
        c_assert(n_in == strlen(string) - 2);

        c_shquote_skip_char(&in, &n_in);
        c_assert(in == string + 3);
        c_assert(n_in == strlen(string) - 3);
}
static void test_skip_char(void) {
        const char *string = "foo";
        const char *in = string;
        size_t n_in = strlen(string);

        c_shquote_skip_char(&in, &n_in);
        c_assert(in == string + 1);
        c_assert(n_in == strlen(string) - 1);

        c_shquote_skip_char(&in, &n_in);
        c_assert(in == string + 2);
        c_assert(n_in == strlen(string) - 2);

        c_shquote_skip_char(&in, &n_in);
        c_assert(in == string + 3);
        c_assert(n_in == strlen(string) - 3);
}