test-resolved-packet: add a simple test for our allocation functions

src/resolve/meson.build

@@ -160,6 +160,15 @@ tests += [
           libm],
          'ENABLE_RESOLVED'],
 
+        [['src/resolve/test-resolved-packet.c',
+          basic_dns_sources,
+          dns_type_headers],
+         [],
+         [libgcrypt,
+          libgpg_error,
+          libm],
+         'ENABLE_RESOLVED'],
+
         [['src/resolve/test-dnssec.c',
           basic_dns_sources,
           dns_type_headers],

src/resolve/test-resolved-packet.c

@@ -0,0 +1,45 @@
+/***
+  This file is part of systemd
+
+  Copyright 2017 Zbigniew Jędrzejewski-Szmek
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include "log.h"
+#include "resolved-dns-packet.h"
+
+static void test_dns_packet_new(void) {
+        size_t i;
+
+        for (i = 0; i < DNS_PACKET_SIZE_MAX + 2; i++) {
+                _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL;
+
+                assert_se(dns_packet_new(&p, DNS_PROTOCOL_DNS, i) == 0);
+
+                log_debug("dns_packet_new: %zu → %zu", i, p->allocated);
+                assert_se(p->allocated >= MIN(DNS_PACKET_SIZE_MAX, i));
+        }
+}
+
+int main(int argc, char **argv) {
+
+        log_set_max_level(LOG_DEBUG);
+        log_parse_environment();
+        log_open();
+
+        test_dns_packet_new();
+
+        return 0;
+}