def test_wait_until_empty_on_clear(self):
q = Queue(hub=self.hub)
q.append('an item')
q.append('another item')
timeout = 0.5
self.hub.call_later(greennet.greenlet(q.clear), timeout)
start = time.time()
q.wait_until_empty()
duration = time.time() - start
self.assert_(duration < timeout + IMMEDIATE_THRESHOLD
and duration > timeout - IMMEDIATE_THRESHOLD)
