'Ensure that the manager switches URLs to one that works.'

def testURLSwitching(self):

    instrumentor = URLFilter()
    with instrumentor.instrument():
        manager = MockHTTPManager()
        result = manager.OpenServerEndpoint('control')
    self.assertEqual(result.data, 'Good')
    queries = [(x[1]['url'], x[1]['proxies']['http']) for x in instrumentor.actions]
    self.assertEqual(queries, [('http://server1/control', 'proxy1'), ('http://server1/control', 'proxy2'), ('http://server1/control', 'proxy3'), ('http://server2/control', 'proxy1')])
