diff --git a/tests/federation/test_federation_server.py b/tests/federation/test_federation_server.py
index 53082f0c81..33f04e1ff4 100644
--- a/tests/federation/test_federation_server.py
+++ b/tests/federation/test_federation_server.py
@@ -106,8 +106,8 @@ class FederationThirdPartyLookupTests(unittest.FederatingHomeserverTestCase):
 
     def prepare(self, reactor: MemoryReactor, clock: Clock, hs: HomeServer) -> None:
         super().prepare(reactor, clock, hs)
-        self.appservice_handler = hs.get_application_service_handler()
-        self.appservice_handler.query_3pe = AsyncMock(  # type: ignore[method-assign]
+        appservice_handler = hs.get_application_service_handler()
+        self.query_3pe_mock = AsyncMock(
             return_value=[
                 {
                     "userid": "@_xmpp_someone:test",
@@ -116,7 +116,8 @@ class FederationThirdPartyLookupTests(unittest.FederatingHomeserverTestCase):
                 }
             ]
         )
-        self.appservice_handler.get_3pe_protocols = AsyncMock(  # type: ignore[method-assign]
+        appservice_handler.query_3pe = self.query_3pe_mock  # type: ignore[method-assign]
+        appservice_handler.get_3pe_protocols = AsyncMock(  # type: ignore[method-assign]
             return_value={"xmpp": {"instances": []}}
         )
 
@@ -128,7 +129,7 @@ class FederationThirdPartyLookupTests(unittest.FederatingHomeserverTestCase):
         self.assertEqual(
             channel.json_body["results"][0]["userid"], "@_xmpp_someone:test"
         )
-        call = self.appservice_handler.query_3pe.call_args
+        call = self.query_3pe_mock.call_args
         self.assertEqual(call.args[1], "xmpp")
         self.assertEqual(call.args[2], {b"username": [b"someone"]})
 
diff --git a/tests/rest/client/test_thirdparty.py b/tests/rest/client/test_thirdparty.py
index 034b7ade30..4907121172 100644
--- a/tests/rest/client/test_thirdparty.py
+++ b/tests/rest/client/test_thirdparty.py
@@ -58,21 +58,23 @@ class ThirdPartyFederatedLookupTests(unittest.HomeserverTestCase):
         return config
 
     def prepare(self, reactor: MemoryReactor, clock: Clock, hs: HomeServer) -> None:
-        self.appservice_handler = hs.get_application_service_handler()
-        self.appservice_handler.query_3pe = AsyncMock(  # type: ignore[method-assign]
-            return_value=[LOCAL_USER_RESULT]
-        )
-        self.appservice_handler.get_3pe_protocols = AsyncMock(  # type: ignore[method-assign]
+        appservice_handler = hs.get_application_service_handler()
+        self.query_3pe_mock = AsyncMock(return_value=[LOCAL_USER_RESULT])
+        appservice_handler.query_3pe = self.query_3pe_mock  # type: ignore[method-assign]
+        self.get_3pe_protocols_mock = AsyncMock(
             return_value={"xmpp": {"instances": [{"desc": "local xmpp"}]}}
         )
+        appservice_handler.get_3pe_protocols = self.get_3pe_protocols_mock  # type: ignore[method-assign]
 
-        self.transport = hs.get_federation_client().transport_layer
-        self.transport.get_thirdparty_entities = AsyncMock(  # type: ignore[method-assign]
+        transport = hs.get_federation_client().transport_layer
+        self.get_thirdparty_entities_mock = AsyncMock(
             return_value={"results": [REMOTE_USER_RESULT]}
         )
-        self.transport.get_thirdparty_protocols = AsyncMock(  # type: ignore[method-assign]
+        transport.get_thirdparty_entities = self.get_thirdparty_entities_mock  # type: ignore[method-assign]
+        self.get_thirdparty_protocols_mock = AsyncMock(
             return_value={"xmpp": {"instances": [{"desc": "remote xmpp"}]}}
         )
+        transport.get_thirdparty_protocols = self.get_thirdparty_protocols_mock  # type: ignore[method-assign]
 
         self.user = self.register_user("user", "pass")
         self.token = self.login(self.user, "pass")
@@ -85,7 +87,7 @@ class ThirdPartyFederatedLookupTests(unittest.HomeserverTestCase):
         )
         self.assertEqual(channel.code, 200, channel.result)
         self.assertEqual(channel.json_list, [LOCAL_USER_RESULT])
-        self.transport.get_thirdparty_entities.assert_not_called()
+        self.get_thirdparty_entities_mock.assert_not_called()
 
     def test_remote_user_lookup(self) -> None:
         channel = self.make_request(
@@ -96,9 +98,9 @@ class ThirdPartyFederatedLookupTests(unittest.HomeserverTestCase):
         )
         self.assertEqual(channel.code, 200, channel.result)
         self.assertEqual(channel.json_list, [REMOTE_USER_RESULT])
-        self.appservice_handler.query_3pe.assert_not_called()
+        self.query_3pe_mock.assert_not_called()
 
-        call = self.transport.get_thirdparty_entities.call_args
+        call = self.get_thirdparty_entities_mock.call_args
         self.assertEqual(call.args[0], "remote.example.com")
         self.assertEqual(call.args[1], "user")
         self.assertEqual(call.args[2], "xmpp")
@@ -106,7 +108,7 @@ class ThirdPartyFederatedLookupTests(unittest.HomeserverTestCase):
         self.assertEqual(call.args[3], {"username": ["someone"]})
 
     def test_remote_location_lookup(self) -> None:
-        self.transport.get_thirdparty_entities.return_value = {
+        self.get_thirdparty_entities_mock.return_value = {
             "results": [REMOTE_LOCATION_RESULT]
         }
         channel = self.make_request(
@@ -118,7 +120,7 @@ class ThirdPartyFederatedLookupTests(unittest.HomeserverTestCase):
         self.assertEqual(channel.code, 200, channel.result)
         self.assertEqual(channel.json_list, [REMOTE_LOCATION_RESULT])
         self.assertEqual(
-            self.transport.get_thirdparty_entities.call_args.args[1], "location"
+            self.get_thirdparty_entities_mock.call_args.args[1], "location"
         )
 
     def test_remote_protocols(self) -> None:
@@ -131,7 +133,7 @@ class ThirdPartyFederatedLookupTests(unittest.HomeserverTestCase):
         self.assertEqual(
             channel.json_body, {"xmpp": {"instances": [{"desc": "remote xmpp"}]}}
         )
-        self.appservice_handler.get_3pe_protocols.assert_not_called()
+        self.get_3pe_protocols_mock.assert_not_called()
 
     def test_own_server_name_is_local(self) -> None:
         channel = self.make_request(
@@ -141,13 +143,13 @@ class ThirdPartyFederatedLookupTests(unittest.HomeserverTestCase):
         )
         self.assertEqual(channel.code, 200, channel.result)
         self.assertEqual(channel.json_list, [LOCAL_USER_RESULT])
-        self.transport.get_thirdparty_entities.assert_not_called()
+        self.get_thirdparty_entities_mock.assert_not_called()
         # The stripped server param must not reach the local bridges either.
-        fields = self.appservice_handler.query_3pe.call_args.args[2]
+        fields = self.query_3pe_mock.call_args.args[2]
         self.assertNotIn(b"server", fields)
 
     def test_remote_failure_returns_empty(self) -> None:
-        self.transport.get_thirdparty_entities.side_effect = RuntimeError("boom")
+        self.get_thirdparty_entities_mock.side_effect = RuntimeError("boom")
         channel = self.make_request(
             "GET",
             "/_matrix/client/v3/thirdparty/user/xmpp"
@@ -168,14 +170,14 @@ class ThirdPartyFederatedLookupDisabledTests(unittest.HomeserverTestCase):
     ]
 
     def prepare(self, reactor: MemoryReactor, clock: Clock, hs: HomeServer) -> None:
-        self.appservice_handler = hs.get_application_service_handler()
-        self.appservice_handler.query_3pe = AsyncMock(  # type: ignore[method-assign]
-            return_value=[LOCAL_USER_RESULT]
-        )
-        self.transport = hs.get_federation_client().transport_layer
-        self.transport.get_thirdparty_entities = AsyncMock(  # type: ignore[method-assign]
+        appservice_handler = hs.get_application_service_handler()
+        self.query_3pe_mock = AsyncMock(return_value=[LOCAL_USER_RESULT])
+        appservice_handler.query_3pe = self.query_3pe_mock  # type: ignore[method-assign]
+        transport = hs.get_federation_client().transport_layer
+        self.get_thirdparty_entities_mock = AsyncMock(
             return_value={"results": [REMOTE_USER_RESULT]}
         )
+        transport.get_thirdparty_entities = self.get_thirdparty_entities_mock  # type: ignore[method-assign]
 
         self.user = self.register_user("user", "pass")
         self.token = self.login(self.user, "pass")
@@ -189,7 +191,7 @@ class ThirdPartyFederatedLookupDisabledTests(unittest.HomeserverTestCase):
         )
         self.assertEqual(channel.code, 200, channel.result)
         self.assertEqual(channel.json_list, [LOCAL_USER_RESULT])
-        self.transport.get_thirdparty_entities.assert_not_called()
+        self.get_thirdparty_entities_mock.assert_not_called()
         # The server param is still stripped from the bridge query fields.
-        fields = self.appservice_handler.query_3pe.call_args.args[2]
+        fields = self.query_3pe_mock.call_args.args[2]
         self.assertNotIn(b"server", fields)