Fix flakey test

The test was flakey.
The key problem is that the LSPS-server send the list-protocols message
before the LSP-client could send the message

libs/gl-testing/tests/test_lsps.py

@@ -3,6 +3,7 @@
 import json
 
 from glclient.lsps import ProtocolList
+import time
 
 import threading
 
@@ -34,6 +35,7 @@ def wrap_function(*args, **kwargs):
         self._thread = threading.Thread(target=wrap_function, args=args, kwargs=kwargs)
         self._thread.start()
 
+
     def await_result(self, timeout_seconds : float=30.0):
         self._thread.join(timeout=timeout_seconds)
         if self._thread.is_alive():
@@ -68,6 +70,10 @@ def test_lsps_list_protocol(clients : Clients, node_factory : NodeFactory, bitco
     json_rpc_id = "abcdef"
     protocol_fut = AwaitResult(lambda: lsp_client.list_protocols(json_rpc_id=json_rpc_id))
 
+    # The sleep ensures the lsp-client has actually send the message and is ready to receive
+    # the response
+    time.sleep(1.0)
+
     # The n1.rpc.sendcustommsg expects that both the node_id and msg are hex encoded strings
     msg_content = {
         "jsonrpc" : "2.0",