def wait_on_engines(self, timeout=5):
        n = len(self.engines)+self.base_engine_count
        tic = time.time()
        while time.time()-tic < timeout and len(self.client.ids) < n:
            time.sleep(0.1)
        
        assert not len(self.client.ids) < n, "waiting for engines timed out"
wait for our engines to connect.
dataset/ETHPy150Open ipython/ipython-py3k/IPython/parallel/tests/clienttest.py/ClusterTestCase.wait_on_engines