e2e: test connection failure

tests/end_to_end/__main__.py

@@ -468,6 +468,20 @@ if __name__ == '__main__':
                              "<presence from='{jid_one}/{resource_one}' to='#foo%{irc_server_one}/{nick_one}' />"),
                      connection_sequence("irc.localhost", '{jid_one}/{resource_one}'),
                  ]),
+        Scenario("irc_server_connection_failure",
+                 [
+                     handshake_sequence(),
+                     partial(send_stanza,
+                             "<presence from='{jid_one}/{resource_one}' to='#foo%doesnotexist@{biboumi_host}/{nick_one}' />"),
+                     partial(expect_stanza,
+                             "/message/body[text()='Connecting to doesnotexist:6697 (encrypted)']"),
+                     partial(expect_stanza,
+                             "/message/body[text()='Connection failed: Domain name not found']"),
+                     partial(expect_stanza,
+                             ("/presence[@from='#foo%doesnotexist@{biboumi_host}/{nick_one}']/muc:x",
+                              "/presence/error[@type='cancel']/stanza:item-not-found",
+                              "/presence/error[@type='cancel']/stanza:text[text()='Domain name not found']")),
+                 ]),
         Scenario("simple_channel_join",
                  [
                      handshake_sequence(),