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Viewing changes to lib/lp/services/longpoll/testing.py

  • Committer: Jelmer Vernooij
  • Date: 2011-09-21 14:28:02 UTC
  • mfrom: (14006 devel)
  • mto: This revision was merged to the branch mainline in revision 14010.
  • Revision ID: jelmer@canonical.com-20110921142802-7ggkc204igsy532w
Merge lp:launchpad

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lib/lp/services/longpoll/testing.py
 
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# Copyright 2011 Canonical Ltd.  This software is licensed under the
 
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# GNU Affero General Public License version 3 (see the file LICENSE).
 
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"""Things that help with testing of longpoll."""
 
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__metaclass__ = type
 
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__all__ = [
 
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    "capture_longpoll_emissions",
 
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    ]
 
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from collections import namedtuple
 
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from contextlib import contextmanager
 
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from functools import partial
 
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from lp.services.longpoll.adapters import event
 
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LongPollEventRecord = namedtuple(
 
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    "LongPollEventRecord", ("event_key", "data"))
 
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class LoggingRouter:
 
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    """A test double for instances of `RabbitRoutingKey`.
 
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    Saves messages as `LongPollEventRecord` tuples to a log.
 
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    :param log: A callable accepting a single `LongPollEventRecord`.
 
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    :param routing_key: See `RabbitRoutingKey.__init__`.
 
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    """
 
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    def __init__(self, log, routing_key):
 
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        self.log = log
 
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        self.routing_key = routing_key
 
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    def send(self, data):
 
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        record = LongPollEventRecord(self.routing_key, data)
 
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        self.log(record)
 
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@contextmanager
 
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def capture_longpoll_emissions():
 
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    """Capture longpoll emissions while this context is in force.
 
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    This returns a list in which `LongPollEventRecord` tuples will be
 
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    recorded, in the order they're emitted.
 
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    Note that normal event emission is *suppressed globally* while this
 
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    context is in force; *all* events will be stored in the log.
 
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    """
 
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    log = []
 
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    original_router_factory = event.router_factory
 
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    event.router_factory = partial(LoggingRouter, log.append)
 
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    try:
 
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        yield log
 
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    finally:
 
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        event.router_factory = original_router_factory