def test_waiting_for_callbacks(self):

       l = []

       def callback(msg):

           import time; time.sleep(0.2)

           l.append(msg)

       channel = self.gw.remote_exec(source='''

               channel.send(42)

->             ''')

       channel.setcallback(callback)

       channel.waitclose(TESTTIMEOUT) 

       assert l == [42]