start() will throw RuntimeError if called more than once

coolamqp/clustering/cluster.py

@@ -133,7 +133,16 @@ class Cluster(object):
         It is not safe to fork after this.
 
         :param wait: block until connection is ready
+        :raise RuntimeError: called more than once
         """
+
+        try:
+            self.listener
+        except AttributeError:
+            pass
+        else:
+            raise RuntimeError(u'This was already called!')
+
         self.listener = ListenerThread()
 
         self.attache_group = AttacheGroup()

tests/test_clustering/test_things.py

+# coding=UTF-8
+
+from __future__ import print_function, absolute_import, division
+import six
+import unittest
+import time, logging, threading, monotonic
+from coolamqp.objects import Message, MessageProperties, NodeDefinition, Queue, ReceivedMessage, Exchange
+from coolamqp.clustering import Cluster, MessageReceived, NothingMuch
+
+import time
+NODE = NodeDefinition('127.0.0.1', 'guest', 'guest', heartbeat=20)
+logging.basicConfig(level=logging.DEBUG)
+
+
+class TestConnecting(unittest.TestCase):
+
+    def test_start_called_multiple_times(self):
+        c = Cluster([NODE])
+        c.start(wait=True)
+        self.assertRaises(RuntimeError, lambda: c.start())
+        c.shutdown(wait=True)