Do not send NICK command when nick not changed

If we get a presence, that is not always a nick change. Don't bother the
IRC server with a command to change the nick if we're not changing it.

src/bridge/bridge.cpp

@@ -596,6 +596,9 @@ void Bridge::send_irc_nick_change(const Iid& iid, const std::string& new_nick, c
   if (!res_in_chan)
     return;
   IrcClient* irc = this->get_irc_client(iid.get_server());
+  if (new_nick == irc->get_own_nick())
+    return;
+
   irc->send_nick_command(new_nick);
 }
 

tests/end_to_end/scenarios/nick_not_changed.py

@@ -0,0 +1,12 @@
+from scenarios import *
+
+scenario = (
+    send_stanza("<presence from='{jid_one}/{resource_one}' to='#foo%{irc_server_one}/{nick_one}' ><x xmlns='http://jabber.org/protocol/muc'/></presence>"),
+    sequences.connection(),
+    expect_stanza("/presence[@to='{jid_one}/{resource_one}'][@from='#foo%{irc_server_one}/{nick_one}']/muc_user:x/muc_user:item[@affiliation='admin'][@role='moderator']",
+                  "/presence/muc_user:x/muc_user:status[@code='110']"),
+    expect_stanza("/message[@from='#foo%{irc_server_one}'][@type='groupchat']/subject[not(text())]"),
+
+    # Presence with the current nick (status update) should be ignored (no error, no change)
+    send_stanza("<presence from='{jid_one}/{resource_one}' to='#foo%{irc_server_one}/{nick_one}'><show>away</show></presence>"),
+)