No test.log output under Twisted/trial runner

[Eric P. Mangold]

Expecting _trial_temp/test.log to contain logging output. Do get expected output when using normal twisted.trial.unittest.TestCase.

Not sure what the console message regarding "twisted-log" is all about...

% cat junk.py
from testtools import TestCase
from twisted.python import log
from testtools.deferredruntest import AsynchronousDeferredRunTest

class MyTestCase(TestCase):
    run_tests_with = AsynchronousDeferredRunTest

    def test_foo(self):
        log.msg("OH NOZ")
        self.failIf(True)
% trial junk.py
  MyTestCase
    test_foo ... [FAIL]

===============================================================================
[FAIL]: junk.MyTestCase.test_foo

Traceback (most recent call last):
Failure: testtools.testresult.real._StringException: Empty attachments:
  twisted-log

Traceback (most recent call last):
  File "/usr/lib/python2.6/dist-packages/twisted/internet/defer.py", line 125, in maybeDeferred
    result = f(*args, **kw)
  File "/home/teratorn/.local/lib/python2.6/site-packages/testtools/testcase.py", line 566, in _run_test_method
    return self._get_test_method()()
  File "/home/teratorn/code/cattura-support-agent/junk.py", line 10, in test_foo
    self.failIf(True)
  File "/usr/lib/python2.6/unittest.py", line 321, in failIf
    if expr: raise self.failureException, msg
AssertionError

-------------------------------------------------------------------------------
Ran 1 tests in 0.017s

FAILED (failures=1)
% cat _trial_temp/test.log
2012-02-28 10:05:45-0600 [-] Log opened.
2012-02-28 10:05:45-0600 [-] using set_wakeup_fd

[Robert Collins (lifeless)]

I suspect (I haven't checked) that we divert the twisted log to capture it internally - the _trial_temp global is a particular bit of anti-parallel pattern from trials early days that hasn't managed to be purged. There is something definitely wrong here though.

[Jonathan Lange (jml)]

Related to #1515362, I think.

Primary use case is streaming logs that can be watched while running a test (esp. useful when debugging slow / maybe hung tests). Secondary use case is log analysis from a whole test run.

[Jonathan Lange (jml)]

Downstream: https://clusterhq.atlassian.net/browse/FLOC-3469

[Jonathan Lange (jml)]

https://github.com/testing-cabal/testtools/pull/171
https://github.com/testing-cabal/testtools/pull/172