[ZODB-Dev] DisconnectedError during Tests

[Tim Peters]

[Christian Theune]
> I had one or two times the phenomenon that one ZODB test actually failed.
> This is not reliably reproducable and as I'm running the tests "often"
> just since a couple of days and this happened only two or three times,
> I'll ignore this for now that this happened. Here is the traceback
> anyway:

While this does get better as the years drag on, it's still not unusual for
one of the ZEO tests to fail, and especially when run on a slow or
"overloaded" machine.

> ERROR: checkTimeoutProvokingConflicts
(ZEO.tests.testConnection.FileStorageTimeoutTests)
> ----------------------------------------------------------------------
> Traceback (most recent call last):
>   File
"/home/ctheune/Development/ZODB-blobsupport/src/ZEO/tests/ConnectionTests.py
", line 1047, in checkTimeoutProvokingConflicts
>     storage.tpc_finish(t)
>   File
"/home/ctheune/Development/Zope-2.8/lib/python/ZEO/ClientStorage.py", line
1032, in tpc_finish
>     tid = self._server.tpc_finish(id(txn))
>   File "/home/ctheune/Development/Zope-2.8/lib/python/ZEO/ServerStub.py",
line 239, in tpc_finish
>     return self.rpc.call('tpc_finish', id)
>
File"/home/ctheune/Development/ZODB-blobsupport/src/ZEO/zrpc/connection.py",
line 476, in call
>     r_flags, r_args = self.wait(msgid)
>   File
"/home/ctheune/Development/ZODB-blobsupport/src/ZEO/zrpc/connection.py",
line 566, in wait
>     raise DisconnectedError()
> DisconnectedError

I've never seen that particular failure myself.  Jim has seen a failure in
the MappingStorage flavor of the same test, but in a different place; his
failure also showed up once in the overnight testrunner reports, from
Zope-trunk Python-2.4.1c1 : Linux on 17 March 2004:

FAIL: checkTimeoutProvokingConflicts
(ZEO.tests.testConnection.MappingStorageTimeoutTests)
----------------------------------------------------------------------
Traceback (most recent call last):
 File "/usr/local/python2.4/lib/python2.4/unittest.py", line 260, in run
   testMethod()
 File
"/autotest/temp/python24-zope28/lib/python/ZEO/tests/ConnectionTests.py",
line 1014, in checkTimeoutProvokingConflicts
   unless(not storage.is_connected())
 File "/usr/local/python2.4/lib/python2.4/unittest.py", line 309, in
failUnless
   if not expr: raise self.failureException, msg
AssertionError

I just ran it 50 times in a loop on my box, without problems.

These are usually hard to fix, and I don't intend to stare at this one in
the foreseeable future (because I don't have a box on which I can provoke a
failure, I can't even tell whether I'm "making progress").

Cleaning up the tests was a ZODB sprint task we skipped <wink>.