Wait until the stream is closed by the server on user removal

When removing a user over XMPP, the server sends a stream error with
the "User removed" message, and closes the stream afterwards.
Wait until it happens to avoid having incoming messages in the queue
that would cause the wpool process to crash when trying to handle them later.

src/escalus_connection.erl

@@ -34,6 +34,7 @@
          get_tls_last_message/1,
          reset_parser/1,
          is_connected/1,
+         wait_for_close/1,
          wait_for_close/2,
          kill/1,
          use_zlib/1,
@@ -424,6 +425,9 @@ upgrade_to_tls(#client{module = Mod, rcv_pid = Pid, props = Props}) ->
     SSLOpts = proplists:get_value(ssl_opts, Props, []),
     Mod:upgrade_to_tls(Pid, SSLOpts).
 
+wait_for_close(Client) ->
+    wait_for_close(Client, default_timeout()).
+
 %% @doc Waits at most MaxWait ms for the client to be closed.
 %% Returns true if the client was disconnected, otherwise false.
 -spec wait_for_close(client(), non_neg_integer()) -> boolean().

src/escalus_users.erl

@@ -297,7 +297,17 @@ delete_user(Config, {_Name, UserSpec}) ->
     {ok, Conn, _} = escalus_connection:start(Options),
     escalus_connection:send(Conn, escalus_stanza:remove_account()),
     Result = wait_for_result(Conn),
-    escalus_connection:stop(Conn),
+    try
+        {ok, result, _} = Result,
+        StreamError = escalus_connection:get_stanza(Conn, stream_error),
+        escalus:assert(is_stream_error, [<<"conflict">>, <<"User removed">>], StreamError),
+        StreamEnd = escalus_connection:get_stanza(Conn, stream_end),
+        escalus:assert(is_stream_end, StreamEnd),
+        escalus_connection:wait_for_close(Conn)
+    catch C:R:S ->
+            error_logger:error_msg("error when trying to delete user: ~p:~p, stacktrace: ~p~n", [C, R, S]),
+            escalus_connection:stop(Conn)
+    end,
     Result.
 
 -spec auth_type([proplists:property()]) -> {module, atom(), list()} | xmpp.