Test failure: “One or more services are registered” etc.

[Jeroen T. Vermeulen]

When running a full ./bin/test.maas test, I get this failure:

ERROR: maasserver.tests.test_eventloop.TestRegionEventLoop.test_start_and_stop
----------------------------------------------------------------------
_StringException: Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/fixtures/fixture.py", line 112, in cleanUp
    return self._cleanups(raise_errors=raise_first)
  File "/usr/lib/python2.7/dist-packages/fixtures/callmany.py", line 88, in __call__
    reraise(error[0], error[1], error[2])
  File "/usr/lib/python2.7/dist-packages/fixtures/callmany.py", line 82, in __call__
    cleanup(*args, **kwargs)
  File "maas/src/maasserver/testing/eventloop.py", line 54, in checkEventLoopClean
    % ', '.join(service.name for service in services))
RuntimeError: One or more services are registered; this fixture cannot make a reasonable decision about what to do next.

The services in question turn out to be rpc, rpc-advertise, and nonce-cleanup. If I make the code go into pdb at the point where it is about to raise the exception, and I look into loop.services interactively, I get a MultiService object representing an empty list of services. So presumably this is a race that will fix itself given time.

This happens both on my i386-installed laptop and my amd64-installed desktop, both running 14.04.