1 files changed, 25 insertions, 16 deletions
diff --git a/tests/replication/_base.py b/tests/replication/_base.py
index 3379189785..d5dce1f83f 100644
--- a/tests/replication/_base.py
+++ b/tests/replication/_base.py
@@ -212,6 +212,9 @@ class BaseMultiWorkerStreamTestCase(unittest.HomeserverTestCase):
         # Fake in memory Redis server that servers can connect to.
         self._redis_server = FakeRedisPubSubServer()
 
+        # We may have an attempt to connect to redis for the external cache already.
+        self.connect_any_redis_attempts()
+
         store = self.hs.get_datastore()
         self.database_pool = store.db_pool
 
@@ -401,25 +404,23 @@ class BaseMultiWorkerStreamTestCase(unittest.HomeserverTestCase):
         fake one.
         """
         clients = self.reactor.tcpClients
-        self.assertEqual(len(clients), 1)
-        (host, port, client_factory, _timeout, _bindAddress) = clients.pop(0)
-        self.assertEqual(host, "localhost")
-        self.assertEqual(port, 6379)
+        while clients:
+            (host, port, client_factory, _timeout, _bindAddress) = clients.pop(0)
+            self.assertEqual(host, "localhost")
+            self.assertEqual(port, 6379)
 
-        client_protocol = client_factory.buildProtocol(None)
-        server_protocol = self._redis_server.buildProtocol(None)
+            client_protocol = client_factory.buildProtocol(None)
+            server_protocol = self._redis_server.buildProtocol(None)
 
-        client_to_server_transport = FakeTransport(
-            server_protocol, self.reactor, client_protocol
-        )
-        client_protocol.makeConnection(client_to_server_transport)
-
-        server_to_client_transport = FakeTransport(
-            client_protocol, self.reactor, server_protocol
-        )
-        server_protocol.makeConnection(server_to_client_transport)
+            client_to_server_transport = FakeTransport(
+                server_protocol, self.reactor, client_protocol
+            )
+            client_protocol.makeConnection(client_to_server_transport)
 
-        return client_to_server_transport, server_to_client_transport
+            server_to_client_transport = FakeTransport(
+                client_protocol, self.reactor, server_protocol
+            )
+            server_protocol.makeConnection(server_to_client_transport)
 
 
 class TestReplicationDataHandler(GenericWorkerReplicationHandler):
@@ -624,6 +625,12 @@ class FakeRedisPubSubProtocol(Protocol):
             (channel,) = args
             self._server.add_subscriber(self)
             self.send(["subscribe", channel, 1])
+
+        # Since we use SET/GET to cache things we can safely no-op them.
+        elif command == b"SET":
+            self.send("OK")
+        elif command == b"GET":
+            self.send(None)
         else:
             raise Exception("Unknown command")
 
@@ -645,6 +652,8 @@ class FakeRedisPubSubProtocol(Protocol):
             # We assume bytes are just unicode strings.
             obj = obj.decode("utf-8")
 
+        if obj is None:
+            return "$-1\r\n"
         if isinstance(obj, str):
             return "${len}\r\n{str}\r\n".format(len=len(obj), str=obj)
         if isinstance(obj, int):