diff --git a/modoboa/policyd/tests.py b/modoboa/policyd/tests.py
index c0eba548b..d3bd97000 100644
--- a/modoboa/policyd/tests.py
+++ b/modoboa/policyd/tests.py
@@ -1,7 +1,8 @@
 """Policy daemon related tests."""
 
 import asyncio
-from mock import patch
+from aiosmtplib import send
+from unittest.mock import AsyncMock
 from multiprocessing import Process
 import socket
 import time
@@ -56,8 +57,7 @@ class PolicyDaemonTestCase(
         self.admin.role = "SuperAdmins"
 
         db.connections.close_all()
-        patcher = patch("aiosmtplib.send")
-        self.send_mock = patcher.start()
+        self.send_mock = AsyncMock(send)
         self.process = Process(target=start_policy_daemon)
         self.process.daemon = True
         self.process.start()