tests/relay: fix crash in tests on Alpine 3.18

ChangeLog.adoc

@@ -13,6 +13,10 @@ For a list of important changes that require manual actions, please look at rele
 [[v4.0.2]]
 == Version 4.0.2 (under dev)
 
+Tests::
+
+  * relay: fix crash in tests on Alpine 3.18
+
 Build::
 
   * php: fix detection of PHP 8.2 on Alpine 3.18

src/plugins/relay/irc/relay-irc.c

@@ -206,7 +206,7 @@ relay_irc_sendf (struct t_relay_client *client, const char *format, ...)
     const char *str_message, *ptr_msg1, *ptr_msg2;
     struct t_hashtable *hashtable_in, *hashtable_out;
 
-    if (!client)
+    if (!client || !format)
         return;
 
     weechat_va_format (format);

tests/unit/plugins/relay/irc/test-relay-irc.cpp

@@ -487,7 +487,6 @@ TEST(RelayIrc, RelayIrcMessageParse)
 
 TEST(RelayIrcWithClient, RelayIrcSendf)
 {
-
     relay_irc_sendf (NULL, NULL);
     relay_irc_sendf (NULL, "test");
     relay_irc_sendf (ptr_relay_client, NULL);