diff --git a/tests/unit/test_plugin_xep_0461.py b/tests/unit/test_plugin_xep_0461.py
new file mode 100644
index 00000000..69b44df4
--- /dev/null
+++ b/tests/unit/test_plugin_xep_0461.py
@@ -0,0 +1,96 @@
+#!/usr/bin/env python3
+
+# Libervia: an XMPP client
+# Copyright (C) 2009-2025 Jérôme Poisson (goffi@goffi.org)
+
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+
+from unittest.mock import MagicMock, patch
+
+import pytest
+from twisted.words.protocols.jabber import jid
+from twisted.words.xish import domish
+
+from libervia.backend.core import exceptions
+from libervia.backend.memory.sqla_mapping import History
+from libervia.backend.models.core import MessageData
+from libervia.backend.plugins.plugin_xep_0461 import NS_REPLY, ReplyTo, XEP_0461
+from pytest_twisted import ensureDeferred as ed
+
+
+class TestXEP0461:
+    @ed
+    async def test_reply_to_from_element(self):
+        """<reply> element parsing works."""
+        # Test correct case
+        element = domish.Element((NS_REPLY, "reply"), attribs={"id": "123", "to": "user@example.com"})
+        reply = ReplyTo.from_element(element)
+        assert reply.to == jid.JID("user@example.com")
+        assert reply.id == "123"
+        assert not reply.internal_uid
+
+        # Test child element
+        parent = domish.Element((None, "some"))
+        child = domish.Element((NS_REPLY, "reply"), attribs={"id": "456"})
+        parent.addChild(child)
+        reply = ReplyTo.from_element(parent)
+        assert reply.id == "456"
+        assert reply.to is None
+
+        # Test missing id
+        element = domish.Element((NS_REPLY, "reply"))
+        with pytest.raises(exceptions.DataError):
+            ReplyTo.from_element(element)
+
+        # Test no reply
+        element = domish.Element((None, "some"))
+        with pytest.raises(exceptions.NotFound):
+            ReplyTo.from_element(element)
+
+    @ed
+    async def test_reply_to_to_element(self, host, client):
+        "<reply> element generation works."
+        reply = ReplyTo(id="123", internal_uid=True)
+        with pytest.raises(exceptions.DataError):
+            reply.to_element()
+
+        reply = ReplyTo(id="123", internal_uid=False)
+        elt = reply.to_element()
+        assert elt.uri == NS_REPLY
+        assert elt.name == "reply"
+        assert elt["id"] == "123"
+        assert not elt.hasAttribute("to")
+
+        reply = ReplyTo(id="123", to=jid.JID("user@example.com"), internal_uid=False)
+        elt = reply.to_element()
+        assert elt["to"] == "user@example.com"
+
+    @ed
+    async def test_xep_0461_message_received_trigger(self, host, client):
+        """post_treat callback is added."""
+        xep = XEP_0461(host)
+        post_treat = MagicMock()
+        xep._message_received_trigger(client, None, post_treat)
+        assert post_treat.addCallback.called
+
+    @ed
+    async def test_xep_0461_send_message_trigger(self, host, client):
+        "post_xml_treatments callback is added."
+        xep = XEP_0461(host)
+        mess_data = MessageData(extra={"reply": {"id": "123", "internal_uid": False}})
+        pre_xml_treatments = MagicMock()
+        post_xml_treatments = MagicMock()
+        xep._sendMessage_trigger(client, mess_data, pre_xml_treatments, post_xml_treatments)
+        assert post_xml_treatments.addCallback.called