[Zope-Coders] Unittests for 2.7 failing in a unpredictable way

[Andreas Jung]

I have been running the 2.7 unittests today multiple times. Sometimes they 
pass, sometimes they fail
when running unchanged inside the same sandbox (Python 2.3.3, Linux):

======================================================================
ERROR: checkConcurrentLargeUpdates 
(ZEO.tests.testConnection.FileStorageConnectionTests)
----------------------------------------------------------------------
Traceback (most recent call last):
  File 
"/develop/sandboxes/Zope-2_7-branch/Zope/lib/python/ZEO/tests/InvalidationTests.py", 
line 552, in checkConcurr
ntLargeUpdates
    get_transaction().commit()
  File 
"/develop/sandboxes/Zope-2_7-branch/Zope/lib/python/ZODB/Transaction.py", 
line 241, in commit
    ncommitted += self._commit_objects(objects)
  File 
"/develop/sandboxes/Zope-2_7-branch/Zope/lib/python/ZODB/Transaction.py", 
line 356, in _commit_objects
    jar.commit(o, self)
  File 
"/develop/sandboxes/Zope-2_7-branch/Zope/lib/python/ZODB/Connection.py", 
line 348, in commit
    raise ReadConflictError(object=object)
ReadConflictError: database read conflict error (oid 0x0f, class 
BTrees.OOBTree.OOBucket)

======================================================================
FAIL: checkConcurrentUpdates2StoragesMT 
(ZEO.tests.testConnection.FileStorageConnectionTests)
----------------------------------------------------------------------
Traceback (most recent call last):
  File 
"/develop/sandboxes/Zope-2_7-branch/Zope/lib/python/ZEO/tests/InvalidationTests.py", 
line 476, in checkConcurr
ntUpdates2StoragesMT
    self._check_threads(tree, t1, t2, t3)
  File 
"/develop/sandboxes/Zope-2_7-branch/Zope/lib/python/ZEO/tests/InvalidationTests.py", 
line 373, in _check_threa
s
    self.fail('\n'.join(errormsgs))
  File "/opt/python-2.3.4/lib/python2.3/unittest.py", line 270, in fail
    raise self.failureException, msg
AssertionError: expected keys != actual keys
key 263 expected but not in tree

======================================================================
FAIL: checkSecondBeginFails (ZEO.tests.testZEO.MappingStorageTests)
----------------------------------------------------------------------
Traceback (most recent call last):
  File 
"/develop/sandboxes/Zope-2_7-branch/Zope/lib/python/ZEO/tests/ThreadTests.py", 
line 110, in checkSecondBeginFa
ls
    thread2.join()
  File 
"/develop/sandboxes/Zope-2_7-branch/Zope/lib/python/ZEO/tests/ThreadTests.py", 
line 39, in join
    assert not self.isAlive()
AssertionError

======================================================================
FAIL: check7ZODBThreads (ZODB.tests.testFileStorage.FileStorageTests)
----------------------------------------------------------------------
Traceback (most recent call last):
  File 
"/develop/sandboxes/Zope-2_7-branch/Zope/lib/python/ZODB/tests/MTStorage.py", 
line 217, in check7ZODBThreads
    self._checkNThreads(7, ZODBClientThread, db, self)
  File 
"/develop/sandboxes/Zope-2_7-branch/Zope/lib/python/ZODB/tests/MTStorage.py", 
line 206, in _checkNThreads
    t.join(60)
  File 
"/develop/sandboxes/Zope-2_7-branch/Zope/lib/python/ZODB/tests/MTStorage.py", 
line 41, in run
    self.runtest()
  File 
"/develop/sandboxes/Zope-2_7-branch/Zope/lib/python/ZODB/tests/MTStorage.py", 
line 70, in runtest
    self.test.fail()
  File "/opt/python-2.3.4/lib/python2.3/unittest.py", line 270, in fail
    raise self.failureException, msg
AssertionError

Any ideas what might go wrong?

Andreas