_pythonpath only sometimes importable in tests

[Jonathan Lange]

If you write a test like this::

  class TestSomething(TestCase):
    def test_a_thing(self):
      import _pythonpath

And run it by itself, it will fail, being unable to import _pythonpath. However, there are tests in the Launchpad test suite (notably, lp.services.job.tests.test_runner.TestTwistedJobRunner) that do that successfully when run as part of the whole test suite, but fail when run stand alone.

[Jonathan Lange (jml)]

Some debugging notes:

  * This appears to be unrelated to bug 505913
  * As best as I can tell, this is nothing to do with zope.testing's knack of running much of the suite in subprocesses. I've tried various combinations of ZopeTestInSubProcess and running the test after a layer that cannot be torn down and nothing seems to affect importing _pythonpath

[Jonathan Lange (jml)]

As far as I can tell, the only in-process manipulation of sys.path comes from test_shhh, which adds the 'utilities' directory to sys.path on import. utilities contains a _pythonpath, and this would explain how this test can pass when run in isolation.

[Jonathan Lange (jml)]

It's definitely test_shhh's fault. For lp.services.job.tests.test_runner.TestTwistedJobRunner, I've done the sys.path manipulation manually. To fix this bug properly, test_shhh needs to clean up after itself.

[Robert Collins (lifeless)]

test_sssh should use a proper namespace to import stuff :) probably want to build it in buildout too.