diff --git a/tests/handlers/test_appservice.py b/tests/handlers/test_appservice.py
index a667fb6f0..b75345594 100644
--- a/tests/handlers/test_appservice.py
+++ b/tests/handlers/test_appservice.py
@@ -31,6 +31,7 @@ class AppServiceHandlerTestCase(unittest.TestCase):
         self.mock_scheduler = Mock()
         hs = Mock()
         hs.get_datastore = Mock(return_value=self.mock_store)
+        self.mock_store.get_received_ts.return_value = 0
         hs.get_application_service_api = Mock(return_value=self.mock_as_api)
         hs.get_application_service_scheduler = Mock(return_value=self.mock_scheduler)
         hs.get_clock.return_value = MockClock()