caddy-frontend/test: Add TODO entry about socket ready loop

software/caddy-frontend/test/test.py

@@ -2639,6 +2639,7 @@ http://apachecustomhttpsaccepted.example.com:%%(http_port)s {
     finally:
       self.getSupervisorRPCServer().supervisor.startProcess(caddy_process_name)
       time.sleep(2)  # give few moments for caddy to start
+                     # XXX: convert to a loop which awaits caddy to be ready
     # END: check stale-if-error support
 
     result_direct = self.fakeHTTPResult(