From e5a82eba5b937d2faf37ef55a0179dfbbbaa587c Mon Sep 17 00:00:00 2001
From: ErikBrown2 <32511867+ErikBrown2@users.noreply.github.com>
Date: Sun, 30 Aug 2026 13:14:51 +0200
Subject: [PATCH] Add regression test for ADVERT_PATH zero bytes

Verify that embedded 0x00 bytes in multi-byte ADVERT_PATH hashes are preserved during parsing.
---
 tests/unit/test_reader.py | 27 ++++++++++++++++++++++++++-
 1 file changed, 26 insertions(+), 1 deletion(-)

diff --git a/tests/unit/test_reader.py b/tests/unit/test_reader.py
index 758968e..2abc906 100644
--- a/tests/unit/test_reader.py
+++ b/tests/unit/test_reader.py
@@ -277,4 +277,29 @@ async def test_parse_packet_payload_txt_type_decodes_high_bits():
     )
     assert log_data["attempt"] == 1, (
         f"Expected attempt=1, got {log_data['attempt']}"
-    )
\ No newline at end of file
+    )
+
+
+@pytest.mark.asyncio
+async def test_advert_path_preserves_embedded_zero_bytes():
+    """ADVERT_PATH must preserve valid 0x00 bytes inside path hashes."""
+    dispatcher = _CapturingDispatcher()
+    reader = MessageReader(dispatcher)
+
+    # ADVERT_PATH (0x0e), 2 hops, 3-byte hashes.
+    # path_len byte: hash mode 2 (3 bytes) + 2 hops = 0x82.
+    # The first hash deliberately contains an embedded 0x00 byte.
+    packet = bytearray.fromhex("0e8212003456789a")
+
+    await reader.handle_rx(packet)
+
+    advert_path_events = [
+        e for e in dispatcher.events if e.type == EventType.ADVERT_PATH
+    ]
+
+    assert len(advert_path_events) == 1
+
+    payload = advert_path_events[0].payload
+    assert payload["path_hash_mode"] == 2
+    assert payload["path_len"] == 2
+    assert payload["path"] == "12003456789a"