From 839397545966a287592b1700aab379b46cf3f47a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Lo=C3=AFc=20Hoguin?= <essen@ninenines.eu>
Date: Thu, 5 Jun 2025 15:38:28 +0200
Subject: [PATCH] Confirm handler terminates with AppCode/AppMsg

---
 test/draft_h3_webtransport_SUITE.erl | 26 ++++++++++++++++++++++++++
 test/handlers/wt_echo_h.erl          |  8 +++++++-
 2 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/test/draft_h3_webtransport_SUITE.erl b/test/draft_h3_webtransport_SUITE.erl
index 2f1a1631..b271f590 100644
--- a/test/draft_h3_webtransport_SUITE.erl
+++ b/test/draft_h3_webtransport_SUITE.erl
@@ -482,6 +482,32 @@ close_wt_session_server(Config) ->
 %% Application Error Message: A UTF-8 encoded error message string provided by the application closing the session. The message takes up the remainder of the capsule, and its length MUST NOT exceed 1024 bytes. (6)
 
 %% @todo close_wt_session_app_code_msg_client
+close_wt_session_app_code_msg_client(Config) ->
+	doc("The WT client can close a single session with an application error code "
+		"and an application error message. (draft_webtrans_http3 4.6)"),
+	%% Connect to the WebTransport server.
+	#{
+		conn := Conn,
+		connect_stream_ref := ConnectStreamRef,
+		session_id := SessionID
+	} = do_webtransport_connect(Config),
+	%% Create a bidi stream, send a special instruction to make it propagate events.
+	{ok, LocalStreamRef} = quicer:start_stream(Conn, #{}),
+	EventPidBin = term_to_binary(self()),
+	{ok, _} = quicer:send(LocalStreamRef, <<1:2, 16#41:14, 0:2, SessionID:6,
+		"TEST:event_pid:", EventPidBin/binary>>),
+	%% Send the CLOSE_WEBTRANSPORT_SESSION capsule on the CONNECT stream.
+	{ok, _} = quicer:send(ConnectStreamRef,
+		cow_capsule:close_wt_session(17, <<"seventeen">>),
+		?QUIC_SEND_FLAG_FIN),
+	%% @todo Stop reading from the CONNECt stream too. (STOP_SENDING)
+	%% Receive the terminate event from the WT handler.
+	receive
+		{'$wt_echo_h', terminate, {closed, 17, <<"seventeen">>}, _, _} ->
+			ok
+	after 1000 ->
+		error({timeout, waiting_for_terminate_event})
+	end.
 
 close_wt_session_app_code_server(Config) ->
 	doc("The WT server can close a single session with an application error code. "
diff --git a/test/handlers/wt_echo_h.erl b/test/handlers/wt_echo_h.erl
index 7bb786be..bb68e392 100644
--- a/test/handlers/wt_echo_h.erl
+++ b/test/handlers/wt_echo_h.erl
@@ -57,7 +57,9 @@ webtransport_handle(Event = {stream_data, _StreamID, _IsFin, <<"TEST:", Test/bit
 		<<"close_app_code">> ->
 			{[{close, 1234567890}], Streams};
 		<<"close_app_code_msg">> ->
-			{[{close, 1234567890, <<"onetwothreefourfivesixseveneightnineten">>}], Streams}
+			{[{close, 1234567890, <<"onetwothreefourfivesixseveneightnineten">>}], Streams};
+		<<"event_pid:", EventPidBin/bits>> ->
+			{[], Streams#{event_pid => binary_to_term(EventPidBin)}}
 	end;
 webtransport_handle(Event = {stream_data, StreamID, IsFin, Data}, Streams) ->
 	ct:pal("WT handle ~p~n", [Event]),
@@ -85,6 +87,10 @@ webtransport_info({try_again, Event}, Streams) ->
 	ct:pal("try_again ~p", [Event]),
 	webtransport_handle(Event, Streams).
 
+terminate(Reason, Req, State=#{event_pid := EventPid}) ->
+	ct:pal("terminate ~p ~p ~p", [Reason, Req, State]),
+	EventPid ! {'$wt_echo_h', terminate, Reason, Req, State},
+	ok;
 terminate(Reason, Req, State) ->
 	ct:pal("terminate ~p ~p ~p", [Reason, Req, State]),
 	ok.