static void test_append_char(void) {
        char c = 'c';
        char buf[1];
        char *out = buf;
        size_t n_out = sizeof(buf);
        int r;

        r = c_shquote_append_char(&out, &n_out, c);
        c_assert(!r);
        c_assert(buf[0] == c);
        c_assert(out == buf + 1);
        c_assert(n_out == sizeof(buf) - 1);

        r = c_shquote_append_char(&out, &n_out, c);
        c_assert(r == C_SHQUOTE_E_NO_SPACE);
}
static void test_append_char(void) {
        char c = 'c';
        char buf[1];
        char *out = buf;
        size_t n_out = sizeof(buf);
        int r;

        r = c_shquote_append_char(&out, &n_out, c);
        c_assert(!r);
        c_assert(buf[0] == c);
        c_assert(out == buf + 1);
        c_assert(n_out == sizeof(buf) - 1);

        r = c_shquote_append_char(&out, &n_out, c);
        c_assert(r == C_SHQUOTE_E_NO_SPACE);
}