1 files changed, 6 insertions, 1 deletions
diff --git a/tests/module_api/test_api.py b/tests/module_api/test_api.py
index 9d38974fba..e915dd5c7c 100644
--- a/tests/module_api/test_api.py
+++ b/tests/module_api/test_api.py
@@ -25,6 +25,7 @@ from synapse.types import create_requester
 
 from tests.events.test_presence_router import send_presence_update, sync_presence
 from tests.replication._base import BaseMultiWorkerStreamTestCase
+from tests.test_utils import simple_async_mock
 from tests.test_utils.event_injection import inject_member_event
 from tests.unittest import HomeserverTestCase, override_config
 from tests.utils import USE_POSTGRES_FOR_TESTS
@@ -46,8 +47,12 @@ class ModuleApiTestCase(HomeserverTestCase):
         self.auth_handler = homeserver.get_auth_handler()
 
     def make_homeserver(self, reactor, clock):
+        # Mock out the calls over federation.
+        fed_transport_client = Mock(spec=["send_transaction"])
+        fed_transport_client.send_transaction = simple_async_mock({})
+
         return self.setup_test_homeserver(
-            federation_transport_client=Mock(spec=["send_transaction"]),
+            federation_transport_client=fed_transport_client,
         )
 
     def test_can_register_user(self):