From c20c71a07919d6553894d390f0f8edbabf2454f4 Mon Sep 17 00:00:00 2001
From: Amaury Denoyelle <adenoyelle@haproxy.com>
Date: Thu, 4 Sep 2025 14:53:03 +0200
Subject: [PATCH] TESTS: quic: add unit-tests for QUIC TX part

Define a new "quic_tx" unit-test which is used to test QUIC TX module.
For the moment, a single test is performed on qc_do_build_pkt(). It
checks that PADDING is correctly added for HP sampling in case of a
small packet.
---
 src/quic_tx.c           | 59 +++++++++++++++++++++++++++++++++++++++++
 tests/unit/quic/quic.sh |  1 +
 2 files changed, 60 insertions(+)

diff --git a/src/quic_tx.c b/src/quic_tx.c
index 4c6d64518..7a2da7eed 100644
--- a/src/quic_tx.c
+++ b/src/quic_tx.c
@@ -2231,6 +2231,65 @@ static struct quic_tx_packet *qc_build_pkt(unsigned char **pos,
 	TRACE_DEVEL("leaving on error", QUIC_EV_CONN_TXPKT, qc);
 	return NULL;
 }
+
+int quic_tx_unittest(int argc, char **argv)
+{
+	struct quic_conn qc;
+	struct quic_cc_path path;
+	struct quic_pktns pktns;
+	struct quic_enc_level qel;
+	struct quic_tx_packet pkt;
+
+	unsigned char area[1024];
+	unsigned char *end = area + 1024;
+
+	unsigned char *buf_pn;
+	size_t pn_len;
+
+	struct list frms = LIST_HEAD_INIT(frms);
+	struct quic_frame frm;
+
+	/* Minimal quic_conn init and linked elements to be able to use
+	 * qc_do_build_pkt() safely.
+	 */
+	qc.dcid.len = 8;
+	qc.scid.len = 8;
+
+	qc.path = &path;
+	path.prep_in_flight = 0;
+	path.cwnd = 16384;
+
+	qel.pktns = &pktns;
+	pktns.rx.largest_acked_pn = 0;
+	pktns.tx.pto_probe = 0;
+	pktns.flags = 0;
+
+	/* short header packet */
+	pkt.type = QUIC_PACKET_TYPE_SHORT;
+	LIST_INIT(&pkt.frms);
+
+	/* payload frames content */
+	frm.type = QUIC_FT_MAX_STREAMS_BIDI;
+	frm.max_streams_bidi.max_streams = 4;
+	LIST_APPEND(&frms, &frm.list);
+
+	/* Built a small packet with a single MAX_STREAMS frame. Padding must
+	 * be added so that PN decoding can be performed by the peer.
+	 */
+	qc_do_build_pkt(area, end, 0, &pkt, 0, &pn_len, &buf_pn,
+	                0, 0, 0, 1,
+	                &qel, &qc, NULL, &frms);
+
+	/* Ensure padding has been added to packet.
+	 * packet length = 1 (short hdlen) + 8 (DCID len) + 1 (PN len) + 3 (payload)
+	 * payload       = 2 (MAX_STREAMS frm) + 1 (PADDING)
+	 */
+	BUG_ON(pkt.len != 13 || pn_len  != 1);
+
+	return 0;
+}
+REGISTER_UNITTEST("quic_tx", quic_tx_unittest);
+
 /*
  * Local variables:
  *  c-indent-level: 8
diff --git a/tests/unit/quic/quic.sh b/tests/unit/quic/quic.sh
index ecea5d550..e9f05c688 100755
--- a/tests/unit/quic/quic.sh
+++ b/tests/unit/quic/quic.sh
@@ -6,6 +6,7 @@ check() {
 
 run() {
 	${HAPROXY_PROGRAM} -U quic_enc
+	${HAPROXY_PROGRAM} -U quic_tx
 }
 
 case "$1" in