Add support for Python 3.11

Because `--all` takes precedence over any followup `-a X` on command
line in e.g. `tox -- -a 1`. See

    https://github.com/zopefoundation/ZEO/commit/06f8e1461c05

and

    https://github.com/zopefoundation/ZEO/pull/210#pullrequestreview-1094352596

for details.

/reviewed-by @d-maurer
/reviewed-on https://github.com/zopefoundation/ZODB/pull/368

As suggested by @d-maurer:

https://github.com/zopefoundation/ZODB/pull/368#issuecomment-1233198328
https://github.com/zopefoundation/ZODB/pull/368#issuecomment-1233245299

@d-maurer suggested to use more specific name fow interface describing
model specifications:

https://github.com/zopefoundation/ZODB/pull/368#discussion_r946358653
https://github.com/zopefoundation/ZODB/pull/368#discussion_r946406075

He also noticed several places in the comments that were unclear:

https://github.com/zopefoundation/ZODB/pull/368#discussion_r946364961
https://github.com/zopefoundation/ZODB/pull/368#discussion_r946372400
https://github.com/zopefoundation/ZODB/pull/368#discussion_r946388329

Also fix my oversight where _check_race_xxx_vs_external_disconnect was
left named wrongly.

Suggested by @d-maurer: https://github.com/zopefoundation/ZODB/pull/368#pullrequestreview-1073526911

And add a way to run tests without long tests:

	zope-testrunner --at-level=1

will run tests without those marked as being long.

By default tox continues to run all tests.

Suggested by @d-maurer with the idea to be able to skip long tests that
are unlikely to fail during development:

https://github.com/zopefoundation/ZODB/pull/368#discussion_r946386969

This currently fails for ZEO (see Bug2 in
https://github.com/zopefoundation/ZEO/issues/209 for details):

    (z-dev) kirr@deca:~/src/wendelin/z/ZEO5$ ZEO_MTACCEPTOR=1 zope-testrunner -fvvvx --test-path=src -t check_race_external_invalidate_vs_disconnect
    /home/kirr/src/wendelin/venv/z-dev/bin/zope-testrunner traceio=True
    /home/kirr/src/wendelin/z/ZEO5/src/ZEO/StorageServer.py:51: DeprecationWarning: The mtacceptor module is deprecated and will be removed in ZEO version 6.
      'in ZEO version 6.', DeprecationWarning)
    Running tests at level 1
    Running .BlobAdaptedFileStorageTests tests:
      Set up .BlobAdaptedFileStorageTests in 0.000 seconds.
      Running:
     check_race_external_invalidate_vs_disconnect (ZEO.tests.testZEO.BlobAdaptedFileStorageTests) (1.889 s)

    Failure in test check_race_external_invalidate_vs_disconnect (ZEO.tests.testZEO.BlobAdaptedFileStorageTests)
    Traceback (most recent call last):
      File "/usr/lib/python2.7/unittest/case.py", line 329, in run
        testMethod()
      File "/home/kirr/src/wendelin/z/ZODB/src/ZODB/tests/racetest.py", line 357, in check_race_external_invalidate_vs_disconnect
        T2ObjectsInc2Phase())
      File "/home/kirr/src/wendelin/z/ZODB/src/ZODB/tests/util.py", line 400, in _
        return f(*argv, **kw)
      File "/home/kirr/src/wendelin/z/ZODB/src/ZODB/tests/racetest.py", line 446, in _check_race_xxx_vs_external_disconnect
        self.fail('\n\n'.join([_ for _ in failure if _]))
      File "/usr/lib/python2.7/unittest/case.py", line 410, in fail
        raise self.failureException(msg)
    AssertionError: T15: obj1 (6) - obj2(4) != phase (1)
    obj1._p_serial: 0x03ea4cc505486777  obj2._p_serial: 0x03ea4cc503413799  phase._p_serial: 0x03ea4cc505486777
    zconn_at: 0x03ea4cc505486777  # approximated as max(serials)
    zstor.loadBefore(obj1, @zconn.at)       ->  serial: 0x03ea4cc505486777  next_serial: None
    zstor.loadBefore(obj2, @zconn.at)       ->  serial: 0x03ea4cc504a74099  next_serial: None
    zstor.loadBefore(phase, @zconn.at)      ->  serial: 0x03ea4cc505486777  next_serial: None
    zstor._cache.clear()
    zstor.loadBefore(obj1, @zconn.at)       ->  serial: 0x03ea4cc505486777  next_serial: None
    zstor.loadBefore(obj2, @zconn.at)       ->  serial: 0x03ea4cc504a74099  next_serial: 0x03ea4cc506104155
    zstor.loadBefore(phase, @zconn.at)      ->  serial: 0x03ea4cc505486777  next_serial: 0x03ea4cc506104155

    T51: obj1 (6) - obj2(4) != phase (1)
    obj1._p_serial: 0x03ea4cc505486777  obj2._p_serial: 0x03ea4cc503413799  phase._p_serial: 0x03ea4cc505486777
    zconn_at: 0x03ea4cc505486777  # approximated as max(serials)
    zstor.loadBefore(obj1, @zconn.at)       ->  serial: 0x03ea4cc505486777  next_serial: None
    zstor.loadBefore(obj2, @zconn.at)       ->  serial: 0x03ea4cc503413799  next_serial: None
    zstor.loadBefore(phase, @zconn.at)      ->  serial: 0x03ea4cc505486777  next_serial: None
    zstor._cache.clear()
    zstor.loadBefore(obj1, @zconn.at)       ->  serial: 0x03ea4cc505486777  next_serial: None
    zstor.loadBefore(obj2, @zconn.at)       ->  serial: 0x03ea4cc504a74099  next_serial: None
    zstor.loadBefore(phase, @zconn.at)      ->  serial: 0x03ea4cc505486777  next_serial: None

We will need it in soon for the next test.

Suggested by @d-maurer.

Example failure before this patch:

    Failure in test check_race_load_vs_external_invalidate (ZEO.tests.testZEO.BlobAdaptedFileStorageTests)
    Traceback (most recent call last):
      File "/usr/lib/python2.7/unittest/case.py", line 329, in run
        testMethod()
      File "/home/kirr/src/wendelin/z/ZODB/src/ZODB/tests/racetest.py", line 200, in check_race_load_vs_external_invalidate
        return self._check_race_load_vs_external_invalidate(T2ObjectsInc())
      File "/home/kirr/src/wendelin/z/ZODB/src/ZODB/tests/util.py", line 400, in _
        return f(*argv, **kw)
      File "/home/kirr/src/wendelin/z/ZODB/src/ZODB/tests/racetest.py", line 304, in _check_race_load_vs_external_invalidate
        self.fail([_ for _ in failure if _])
      File "/usr/lib/python2.7/unittest/case.py", line 410, in fail
        raise self.failureException(msg)
    AssertionError: ['T3: obj1 (1)  !=  obj2 (24)\n', 'T4: obj1 (1)  !=  obj2 (24)\n', 'T5: obj1 (1)  !=  obj2 (24)\n', 'T6: obj1 (1)  !=  obj2 (24)\n', 'T7: obj1 (2)  !=  obj2 (24)\n']

Example failure after this patch:

    Failure in test check_race_load_vs_external_invalidate (ZEO.tests.testZEO.BlobAdaptedFileStorageTests)
    Traceback (most recent call last):
      File "/usr/lib/python2.7/unittest/case.py", line 329, in run
        testMethod()
      File "/home/kirr/src/wendelin/z/ZODB/src/ZODB/tests/racetest.py", line 202, in check_race_load_vs_external_invalidate
        return self._check_race_load_vs_external_invalidate(T2ObjectsInc())
      File "/home/kirr/src/wendelin/z/ZODB/src/ZODB/tests/util.py", line 400, in _
        return f(*argv, **kw)
      File "/home/kirr/src/wendelin/z/ZODB/src/ZODB/tests/racetest.py", line 307, in _check_race_load_vs_external_invalidate
        self.fail('\n\n'.join([_ for _ in failure if _]))
      File "/usr/lib/python2.7/unittest/case.py", line 410, in fail
        raise self.failureException(msg)
    AssertionError: T0: obj1 (1)  !=  obj2 (25)
    obj1._p_serial: 0x03ea4be4ea558066  obj2._p_serial: 0x03ea4be4eaac7077
    zconn_at: 0x03ea4be4eaac7077  # approximated as max(serials)
    zstor.loadBefore(obj1, @zconn.at)       ->  serial: 0x03ea4be4ea558066  next_serial: None
    zstor.loadBefore(obj2, @zconn.at)       ->  serial: 0x03ea4be4eaac7077  next_serial: None
    zstor._cache.clear()
    zstor.loadBefore(obj1, @zconn.at)       ->  serial: 0x03ea4be4eaac7077  next_serial: None
    zstor.loadBefore(obj2, @zconn.at)       ->  serial: 0x03ea4be4eaac7077  next_serial: None

    T2: obj1 (1)  !=  obj2 (25)
    obj1._p_serial: 0x03ea4be4ea558066  obj2._p_serial: 0x03ea4be4eaac7077
    zconn_at: 0x03ea4be4eaac7077  # approximated as max(serials)
    zstor.loadBefore(obj1, @zconn.at)       ->  serial: 0x03ea4be4ea558066  next_serial: None
    zstor.loadBefore(obj2, @zconn.at)       ->  serial: 0x03ea4be4eaac7077  next_serial: None
    zstor._cache.clear()
    zstor.loadBefore(obj1, @zconn.at)       ->  serial: 0x03ea4be4eaac7077  next_serial: None
    zstor.loadBefore(obj2, @zconn.at)       ->  serial: 0x03ea4be4eaac7077  next_serial: None

    T3: obj1 (26)  !=  obj2 (25)
    obj1._p_serial: 0x03ea4be4ec6af5cc  obj2._p_serial: 0x03ea4be4eaac7077
    zconn_at: 0x03ea4be4ec6af5cc  # approximated as max(serials)
    zstor.loadBefore(obj1, @zconn.at)       ->  serial: 0x03ea4be4ec6af5cc  next_serial: None
    zstor.loadBefore(obj2, @zconn.at)       ->  serial: 0x03ea4be4eaac7077  next_serial: 0x03ea4be4ec962b00
    zstor._cache.clear()
    zstor.loadBefore(obj1, @zconn.at)       ->  serial: 0x03ea4be4ec6af5cc  next_serial: 0x03ea4be4ec962b00
    zstor.loadBefore(obj2, @zconn.at)       ->  serial: 0x03ea4be4ec6af5cc  next_serial: 0x03ea4be4ec962b00

Introduce the notion of testing model to represent initial state,
eveolution step and maintained invariant in the database.

Refactor tests to accept arbitrary such model and to drive them through
particular testing scenarious that try to hit specific concurrency
issues.

Not only this deduplicates the code a bit, but it also will allow us to
run different models through existing and future checkers. Soon we will
need to run a model with 3 variables (obj1, obj2 and phase) instead of
only 2 (obj1 and obj2) for invalidate / disconnect test.

Please see added module-level documentation for overview.

We are going to add more such tests and related infrastructure. As the
preparatory step take tests added in

- 5b4dd5f7 (tests: Add test for open vs invalidation race), and
- e923c9a8 (tests: Add test for load vs external invalidation race)

and move them to dedicated module.

No functional changes, only plain code movement.

There are small typos in:
- docs/articles/ZODB2.rst
- src/ZODB/Connection.py
- src/ZODB/FileStorage/fsdump.py
- src/ZODB/cross-database-references.rst
- src/ZODB/tests/testblob.py

Fixes:
- Should read `committed` rather than `commited`.
- Should read `resetting` rather than `reseting`.
- Should read `debugging` rather than `debuggin`.
- Should read `constructor` rather than `contructor`.

make blob test `commit_from_wrong_partition` more robust

See previous commit for context: which had to fix
commit_from_wrong_partition this way because without `logger.disabled =
False` logging could not produce its output under Python 3.6.

Discussion1: https://github.com/zopefoundation/ZODB/pull/360#pullrequestreview-936832062
Discussion2: https://github.com/zopefoundation/ZODB/pull/360#issuecomment-1093710722

The blob test `commit_from_wrong_partition` makes use of the logger `ZODB.blob.copied`.

In some cases, this test fails not because the ZODB did something wrong but because the logger is disabled.

At least under Python 3.6, `logging.fileConfig` (and likely all other functions configuring the logging system) disables by default all existing loggers. If logger `ZODB.blob.copied` is already created at that time (i.e. if `ZODB.blob` has been imported), it gets disabled.

The PR adds `logger.disabled = False` to the test `commit_from_wrong_partition` to let it work correctly in those situations.

https://github.com/zopefoundation/ZODB/commit/b6f4cd17cd186cb36025aef44e1cd02934d4fb07

* Config with pure python
* Lint the code.
* Add support for Python 3.9 and 3.10.

Add support for Python 3.9 and 3.10.

Fix `TypeError: can't concat str to bytes` when running fsoids.py script with Python 3.

Closes #350

fsdump/fsstats improvements