Addressed all of Marius' comments from the previous checkin.

src/ZODB/BaseStorage.py

@@ -16,7 +16,7 @@
 The base class here is tightly coupled with its subclasses and
 its use is not recommended.  It's still here for historical reasons.
 """
-from __future__ import print_function, with_statement
+from __future__ import print_function
 
 import threading
 import time

src/ZODB/ConflictResolution.py

@@ -274,7 +274,7 @@ def tryToResolveConflict(self, oid, committedSerial, oldSerial, newpickle,
         if sys.version_info[0] < 3:
             pickler.inst_persistent_id = persistent_id
         else:
-            pickler.inst_persistent_id = persistent_id
+            pickler.persistent_id = persistent_id
         pickler.dump(meta)
         pickler.dump(resolved)
         return self._crs_transform_record_data(file.getvalue(1))

src/ZODB/ExportImport.py

@@ -48,8 +48,8 @@ class ExportImport:
         f.write(b'ZEXP')
         oids = [oid]
         done_oids = {}
-        done=done_oids.__contains__
-        load=self._storage.load
+        done = done_oids.__contains__
+        load = self._storage.load
         supports_blobs = IBlobStorage.providedBy(self._storage)
         while oids:
             oid = oids.pop(0)

src/ZODB/FileStorage/FileStorage.py

@@ -13,7 +13,7 @@
 ##############################################################################
 """Storage implementation using a log written to a single file.
 """
-from __future__ import print_function, with_statement
+from __future__ import print_function
 
 from persistent.TimeStamp import TimeStamp
 from struct import pack, unpack
@@ -129,7 +129,7 @@ class FileStorage(
             raise ValueError("time-travel only supported in read-only mode")
 
         if stop is None:
-            stop=b'\377'*8
+            stop = b'\377'*8
 
         # Lock the database and set up the temp file.
         if not read_only:
@@ -1062,7 +1062,7 @@ class FileStorage(
             raise POSException.ReadOnlyError()
 
         stop = TimeStamp(*time.gmtime(t)[:5]+(t%60,)).raw()
-        if stop==z64:
+        if stop == z64:
             raise FileStorageError('Invalid pack time')
 
         # If the storage is empty, there's nothing to do.

src/ZODB/FileStorage/fsoids.py

-from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
 ##############################################################################
 #
 # Copyright (c) 2004 Zope Foundation and Contributors.
@@ -17,7 +11,7 @@ from __future__ import print_function
 # FOR A PARTICULAR PURPOSE
 #
 ##############################################################################
-
+from __future__ import print_function
 import ZODB.FileStorage
 from ZODB.utils import get_pickle_metadata, p64, oid_repr, tid_repr
 from ZODB.serialize import get_refs

src/ZODB/FileStorage/tests.py

@@ -34,18 +34,22 @@ checker = renormalizing.RENormalizing([
 def pack_keep_old():
     """Should a copy of the database be kept?
 
-The pack_keep_old constructor argument controls whether a .old file (and .old directory for blobs is kept.)
+The pack_keep_old constructor argument controls whether a .old file (and .old
+directory for blobs is kept.)
 
     >>> fs = ZODB.FileStorage.FileStorage('data.fs', blob_dir='blobs')
     >>> db = ZODB.DB(fs)
     >>> conn = db.open()
     >>> import ZODB.blob
     >>> conn.root()[1] = ZODB.blob.Blob()
-    >>> _ = conn.root()[1].open('w').write(b'some data')
+    >>> with conn.root()[1].open('w') as file:
+    ...     _ = file.write(b'some data')
     >>> conn.root()[2] = ZODB.blob.Blob()
-    >>> _ = conn.root()[2].open('w').write(b'some data')
+    >>> with conn.root()[2].open('w') as file:
+    ...     _ = file.write(b'some data')
     >>> transaction.commit()
-    >>> _ = conn.root()[1].open('w').write(b'some other data')
+    >>> with conn.root()[1].open('w') as file:
+    ...     _ = file.write(b'some other data')
     >>> del conn.root()[2]
     >>> transaction.commit()
     >>> old_size = os.stat('data.fs').st_size
@@ -77,11 +81,14 @@ The pack_keep_old constructor argument controls whether a .old file (and .old di
     >>> db = ZODB.DB(fs)
     >>> conn = db.open()
     >>> conn.root()[1] = ZODB.blob.Blob()
-    >>> _ = conn.root()[1].open('w').write(b'some data')
+    >>> with conn.root()[1].open('w') as file:
+    ...     file.write(b'some data')
     >>> conn.root()[2] = ZODB.blob.Blob()
-    >>> _ = conn.root()[2].open('w').write(b'some data')
+    >>> with conn.root()[2].open('w') as file:
+    ...     _ = file.write(b'some data')
     >>> transaction.commit()
-    >>> _ = conn.root()[1].open('w').write(b'some other data')
+    >>> with conn.root()[1].open('w') as file:
+    ...     _ = file.write(b'some other data')
     >>> del conn.root()[2]
     >>> transaction.commit()
 
@@ -117,7 +124,8 @@ def pack_with_repeated_blob_records():
 
     >>> trans = tm.begin()
     >>> fs.tpc_begin(trans)
-    >>> _ = open('ablob', 'w').write('some data')
+    >>> with open('ablob', 'w') as file:
+    ...     _ = file.write('some data')
     >>> _ = fs.store(oid, oldserial, blob_record, '', trans)
     >>> _ = fs.storeBlob(oid, oldserial, blob_record, 'ablob', '', trans)
     >>> fs.tpc_vote(trans)
@@ -182,11 +190,9 @@ def test_suite():
         doctest.DocFileSuite(
             'zconfig.txt', 'iterator.test',
             setUp=ZODB.tests.util.setUp, tearDown=ZODB.tests.util.tearDown,
-            checker=checker
-            ),
+            checker=checker),
         doctest.DocTestSuite(
             setUp=ZODB.tests.util.setUp, tearDown=ZODB.tests.util.tearDown,
-            checker=checker
-            ),
+            checker=checker),
         ))
 

src/ZODB/blob.py

@@ -81,7 +81,8 @@ class Blob(persistent.Persistent):
             raise TypeError('Blobs do not support subclassing.')
         self.__setstate__()
         if data is not None:
-            self.open('w').write(data)
+            with self.open('w') as file:
+                file.write(data)
 
     def __setstate__(self, state=None):
         # we use lists here because it will allow us to add and remove

src/ZODB/fsIndex.py

@@ -38,9 +38,6 @@
 # high-order bytes when saving. On loading data, we add the leading
 # bytes back before using u64 to convert the data back to (long)
 # integers.
-
-from __future__ import with_statement
-
 import struct
 
 from BTrees._fsBTree import fsBucket
@@ -189,7 +186,7 @@ class fsIndex(object):
     iterkeys = __iter__
 
     def keys(self):
-        return list(six.iterkeys(self))
+        return list(self.iterkeys())
 
     def iteritems(self):
         for prefix, tree in six.iteritems(self._data):
@@ -205,7 +202,7 @@ class fsIndex(object):
                 yield str2num(value)
 
     def values(self):
-        return list(six.itervalues(self))
+        return list(self.itervalues())
 
     # Comment below applies for the following minKey and maxKey methods
     #

src/ZODB/scripts/analyze.py

-from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-#!/usr/bin/env python2.4
+#!/usr/bin/env python
 
 # Based on a transaction analyzer by Matt Kromer.
-
+from __future__ import print_function
 import pickle
 import sys
 from ZODB.FileStorage import FileStorage

src/ZODB/scripts/checkbtrees.py

-#!/usr/bin/env python2.3
-
+#!/usr/bin/env python
 """Check the consistency of BTrees in a Data.fs
 
 usage: checkbtrees.py data.fs
@@ -8,16 +7,6 @@ Try to find all the BTrees in a Data.fs, call their _check() methods,
 and run them through BTrees.check.check().
 """
 from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-
 import ZODB
 from ZODB.FileStorage import FileStorage
 from BTrees.check import check

src/ZODB/scripts/fsrefs.py

-#!/usr/bin/env python2.3
-
+#!/usr/bin/env python
 ##############################################################################
 #
 # Copyright (c) 2002 Zope Foundation and Contributors.
@@ -63,10 +62,6 @@ revisions of objects; therefore fsrefs cannot find problems in versions or
 in non-current revisions.
 """
 from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-
 import traceback
 
 from ZODB.FileStorage import FileStorage
@@ -110,7 +105,7 @@ def main(path=None):
 
         path, = args
 
-    
+
     fs = FileStorage(path, read_only=1)
 
     # Set of oids in the index that failed to load due to POSKeyError.

src/ZODB/scripts/fsstats.py

-#!/usr/bin/env python2.3
-
+#!/usr/bin/env python2
 """Print details statistics from fsdump output."""
 from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-
 import re
 import sys
 import six

src/ZODB/scripts/fstail.py

-#!/usr/bin/env python2.3
-
+#!/usr/bin/env python
 ##############################################################################
 #
 # Copyright (c) 2001, 2002 Zope Foundation and Contributors.
@@ -15,8 +14,6 @@
 ##############################################################################
 """Tool to dump the last few transactions from a FileStorage."""
 from __future__ import print_function
-from __future__ import print_function
-
 from ZODB.fstools import prev_txn
 
 import binascii

src/ZODB/scripts/fstest.py

-#!/usr/bin/env python2.3
-
+#!/usr/bin/env python
 ##############################################################################
 #
 # Copyright (c) 2001, 2002 Zope Foundation and Contributors.
@@ -13,7 +12,6 @@
 # FOR A PARTICULAR PURPOSE
 #
 ##############################################################################
-
 """Simple consistency checker for FileStorage.
 
 usage: fstest.py [-v] data.fs
@@ -33,7 +31,6 @@ possible for the damage to occur only in the part of the file that
 stores object pickles.  Those errors will go undetected.
 """
 from __future__ import print_function
-from __future__ import print_function
 
 # The implementation is based closely on the read_index() function in
 # ZODB.FileStorage.  If anything about the FileStorage layout changes,

src/ZODB/scripts/migrate.py

-#!/usr/bin/env python2.3
-
+#!/usr/bin/env python
 ##############################################################################
 #
 # Copyright (c) 2001, 2002, 2003 Zope Foundation and Contributors.
@@ -13,7 +12,6 @@
 # FOR A PARTICULAR PURPOSE
 #
 ##############################################################################
-
 """A script to gather statistics while doing a storage migration.
 
 This is very similar to a standard storage's copyTransactionsFrom() method,
@@ -75,25 +73,6 @@ Positional arguments:
         pairs.  E.g. "name=full;frequency=3600"
 """
 from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-
 import re
 import sys
 import time

src/ZODB/scripts/migrateblobs.py

@@ -14,8 +14,6 @@
 """A script to migrate a blob directory into a different layout.
 """
 from __future__ import print_function
-from __future__ import print_function
-
 import logging
 import optparse
 import os

src/ZODB/scripts/netspace.py

-#!/usr/bin/env python2.3
-
+#!/usr/bin/env python
 """Report on the net size of objects counting subobjects.
 
 usage: netspace.py [-P | -v] data.fs
@@ -8,11 +7,6 @@ usage: netspace.py [-P | -v] data.fs
 -v: print info for all objects, even if a traversal path isn't found
 """
 from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-
 import ZODB
 from ZODB.FileStorage import FileStorage
 from ZODB.utils import U64, get_pickle_metadata

src/ZODB/scripts/space.py

-#!/usr/bin/env python2.3
-
+#!/usr/bin/env python
 """Report on the space used by objects in a storage.
 
 usage: space.py data.fs
@@ -9,12 +8,6 @@ The current implementation only supports FileStorage.
 Current limitations / simplifications: Ignores revisions and versions.
 """
 from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-
 from ZODB.FileStorage import FileStorage
 from ZODB.utils import U64, get_pickle_metadata
 import six

src/ZODB/scripts/zodbload.py

-#!/usr/bin/env python2.3
-
+#!/usr/bin/env python
 ##############################################################################
 #
 # Copyright (c) 2003 Zope Foundation and Contributors.
@@ -112,14 +111,8 @@ Usage: loadmail2 [options]
          -mbox 'foo.mbox 300 -100'
 
        are equivalent
-
-$Id$
 """
 from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-from __future__ import print_function
-
 import mailbox
 import math
 import os
@@ -129,8 +122,6 @@ import sys
 import threading
 import time
 import transaction
-from six.moves import filter
-import six
 
 class JobProducer:
 
@@ -189,7 +180,7 @@ class MBox:
 
         self.number = start
         while min:
-            six.advance_iterator(mb)
+            next(mb)
             min -= 1
 
         self._lock = threading.Lock()
@@ -201,7 +192,7 @@ class MBox:
         try:
             if self._max > 0 and self.number >= self._max:
                 raise IndexError(self.number + 1)
-            message = six.advance_iterator(self._mbox)
+            message = next(self._mbox)
             message.body = message.fp.read()
             message.headers = list(message.headers)
             self.number += 1
@@ -233,7 +224,7 @@ def VmSize():
     except:
         return 0
     else:
-        l = filter(lambda l: l[:7] == 'VmSize:', f.readlines())
+        l = list(filter(lambda l: l[:7] == 'VmSize:', f.readlines()))
         if l:
             l = l[0][7:].strip().split()[0]
             return int(l)
@@ -328,7 +319,7 @@ def run1(tid, db, factory, job, args):
 def run(jobs, tid=b''):
     import Zope2
     while 1:
-        factory, job, args, repeatp = six.advance_iterator(jobs)
+        factory, job, args, repeatp = next(jobs)
         run1(tid, Zope2.DB, factory, job, args)
         if repeatp:
             while 1:
@@ -392,7 +383,7 @@ class IndexJob:
         self.mbox, self.number, self.max = mbox, int(number), int(max)
 
     def create(self):
-        messages = [six.advance_iterator(self.mbox) for i in range(self.number)]
+        messages = [next(self.mbox) for i in range(self.number)]
         return index, (messages, self.catalog, self.max)
 
 

src/ZODB/serialize.py

@@ -449,7 +449,7 @@ class ObjectWriter:
         return self._dump(meta, obj.__getstate__())
 
     def _dump(self, classmeta, state):
-        # To reuse the existing cBytesIO object, we must reset
+        # To reuse the existing BytesIO object, we must reset
         # the file position to 0 and truncate the file after the
         # new pickle is written.
         self._file.seek(0)
@@ -659,6 +659,7 @@ def referencesf(p, oids=None):
         u.noload()
         u.noload()
     else:
+        # Py3: There is no `noload()` in Python 3.
         u.persistent_load = refs.append
         u.load()
         u.load()

src/ZODB/tests/BasicStorage.py

@@ -18,9 +18,6 @@ http://www.zope.org/Documentation/Developer/Models/ZODB/ZODB_Architecture_Storag
 
 All storages should be able to pass these tests.
 """
-
-from __future__ import with_statement
-
 from ZODB import POSException
 from ZODB.tests.MinPO import MinPO
 from ZODB.tests.StorageTestBase import zodb_unpickle, zodb_pickle
@@ -31,8 +28,6 @@ import time
 import transaction
 import zope.interface
 import zope.interface.verify
-from six.moves import map
-from six.moves import zip
 
 ZERO = b'\0'*8
 

src/ZODB/tests/IteratorStorage.py

@@ -144,7 +144,7 @@ class IteratorStorage(IteratorCompare):
 
     def checkIterateRecordsRepeatedly(self):
         self._dostore()
-        tinfo = six.advance_iterator(self._storage.iterator())
+        tinfo = next(self._storage.iterator())
         self.assertEquals(1, len(list(tinfo)))
         self.assertEquals(1, len(list(tinfo)))
 
@@ -152,7 +152,7 @@ class IteratorStorage(IteratorCompare):
         self._dostore()
         iterator = self._storage.iterator()
         # We have one transaction with 1 modified object.
-        txn_1 = six.advance_iterator(iterator)
+        txn_1 = next(iterator)
         self.assertEquals(1, len(list(txn_1)))
 
         # We store another transaction with 1 object, the already running
@@ -187,14 +187,14 @@ class ExtendedIteratorStorage(IteratorCompare):
         txniter = self._storage.iterator(revid2, revid3)
         self.iter_verify(txniter, [revid2, revid3], 12)
         # Specify an upper bound somewhere in between values
-        revid3a = p64(int((U64(revid3) + U64(revid4)) / 2))
+        revid3a = p64((U64(revid3) + U64(revid4)) // 2)
         txniter = self._storage.iterator(revid2, revid3a)
         self.iter_verify(txniter, [revid2, revid3], 12)
         # Specify a lower bound somewhere in between values.
         # revid2 == revid1+1 is very likely on Windows.  Adding 1 before
         # dividing ensures that "the midpoint" we compute is strictly larger
         # than revid1.
-        revid1a = p64(int((U64(revid1) + 1 + U64(revid2)) / 2))
+        revid1a = p64((U64(revid1) + 1 + U64(revid2)) // 2)
         assert revid1 < revid1a
         txniter = self._storage.iterator(revid1a, revid3a)
         self.iter_verify(txniter, [revid2, revid3], 12)

src/ZODB/tests/MTStorage.py

@@ -15,10 +15,6 @@ from ZODB.POSException import ConflictError
 
 SHORT_DELAY = 0.01
 
-def sort(l):
-    "Sort a list in place and return it."
-    return sorted(l)
-
 class TestThread(threading.Thread):
     """Base class for defining threads that run from unittest.
 
@@ -68,7 +64,7 @@ class ZODBClientThread(TestThread):
         else:
             for i in range(self.commits):
                 self.commit(d, i)
-        self.test.assertEqual(sort(d.keys()), list(range(self.commits)))
+        self.test.assertEqual(sorted(d.keys()), list(range(self.commits)))
 
     def commit(self, d, num):
         d[num] = time.time()

src/ZODB/tests/MinPO.py

@@ -12,9 +12,10 @@
 #
 ##############################################################################
 """A minimal persistent object to use for tests"""
-
+import functools
 from persistent import Persistent
 
+@functools.total_ordering
 class MinPO(Persistent):
     def __init__(self, value=None):
         self.value = value
@@ -26,5 +27,8 @@ class MinPO(Persistent):
     def __eq__(self, aMinPO):
         return self.value == aMinPO.value
 
+    def __lt__(self, aMinPO):
+        return self.value <= aMinPO.value
+
     def __repr__(self):
         return "MinPO(%s)" % self.value

src/ZODB/tests/TransactionalUndoStorage.py

@@ -15,7 +15,6 @@
 
 Any storage that supports undo() must pass these tests.
 """
-
 import time
 
 from persistent import Persistent
@@ -29,9 +28,6 @@ from ZODB import DB
 
 from ZODB.tests.MinPO import MinPO
 from ZODB.tests.StorageTestBase import zodb_pickle, zodb_unpickle
-from six.moves import map
-import six
-from six.moves import zip
 
 ZERO = '\0'*8
 
@@ -680,7 +676,7 @@ class TransactionalUndoStorage:
         eq = self.assertEqual
 
         for i in range(BATCHES):
-            txn = six.advance_iterator(transactions)
+            txn = next(transactions)
 
             tid = p64(i + 1)
             eq(txn.tid, tid)
@@ -692,11 +688,11 @@ class TransactionalUndoStorage:
             eq(L1, L2)
 
         for i in range(BATCHES * OBJECTS):
-            txn = six.advance_iterator(transactions)
+            txn = next(transactions)
             eq(len([rec for rec in txn if rec.data_txn is None]), 1)
 
         for i in range(BATCHES):
-            txn = six.advance_iterator(transactions)
+            txn = next(transactions)
 
             # The undos are performed in reverse order.
             otid = p64(BATCHES - i)

src/ZODB/tests/testConnection.py

@@ -12,7 +12,7 @@
 #
 ##############################################################################
 """Unit tests for the Connection class."""
-from __future__ import print_function, with_statement
+from __future__ import print_function
 
 import doctest
 import re
@@ -676,7 +676,7 @@ implementation of checkCurrentSerialInTransaction.
     >>> bad = set()
     >>> def checkCurrentSerialInTransaction(oid, serial, trans):
     ...     six.print_('checkCurrentSerialInTransaction', repr(oid))
-    ...     if not trans == transaction.get(): print('oops')
+    ...     if trans != transaction.get(): print('oops')
     ...     if oid in bad:
     ...         raise ReadConflictError(oid=oid)
 

src/ZODB/tests/testFileStorage.py

@@ -644,7 +644,8 @@ def pack_with_open_blob_files():
     >>> import ZODB.blob
     >>> conn1.root()[1] = ZODB.blob.Blob()
     >>> conn1.add(conn1.root()[1])
-    >>> conn1.root()[1].open('w').write('some data')
+    >>> with conn1.root()[1].open('w') as file:
+    ...     file.write('some data')
     >>> tm1.commit()
 
     >>> tm2 = transaction.TransactionManager()
@@ -652,7 +653,8 @@ def pack_with_open_blob_files():
     >>> f = conn1.root()[1].open()
     >>> conn1.root()[2] = ZODB.blob.Blob()
     >>> conn1.add(conn1.root()[2])
-    >>> conn1.root()[2].open('w').write('some more data')
+    >>> with conn1.root()[2].open('w') as file:
+    ...     file.write('some more data')
 
     >>> db.pack()
     >>> f.read()

src/ZODB/tests/testPersistentMapping.py

@@ -27,7 +27,6 @@ from transaction import Transaction
 import ZODB
 from ZODB.MappingStorage import MappingStorage
 import sys
-import six
 
 try:
     import cPickle
@@ -138,15 +137,15 @@ class PMTests(unittest.TestCase):
         self.assertEqual(items,
                          [('a', 2), ('b', 3), ('name', 'bob'), ('x', 1)])
 
-        keys = list(six.iterkeys(m))
+        keys = list(m.iterkeys())
         keys.sort()
         self.assertEqual(keys, ['a', 'b', 'name', 'x'])
 
-        values = list(six.itervalues(m))
+        values = list(m.itervalues())
         values.sort()
         self.assertEqual(values, [1, 2, 3, 'bob'])
 
-        items = list(six.iteritems(m))
+        items = list(m.iteritems())
         items.sort()
         self.assertEqual(items,
                          [('a', 2), ('b', 3), ('name', 'bob'), ('x', 1)])
@@ -169,7 +168,7 @@ class PMTests(unittest.TestCase):
         keylist = []
         while 1:
             try:
-                key = six.advance_iterator(i)
+                key = next(i)
             except StopIteration:
                 break
             keylist.append(key)

src/ZODB/tests/testUtils.py

@@ -22,7 +22,7 @@ from zope.testing import renormalizing
 from ZODB.utils import U64, p64, u64
 
 try:
-    long(1)
+    long
 except NameError:
     # Py3
     long = int

src/ZODB/tests/testZODB.py

@@ -11,7 +11,6 @@
 # FOR A PARTICULAR PURPOSE.
 #
 ##############################################################################
-
 from persistent import Persistent
 from persistent.mapping import PersistentMapping
 from ZODB.POSException import ReadConflictError
@@ -24,8 +23,6 @@ import ZODB
 import ZODB.FileStorage
 import ZODB.MappingStorage
 import ZODB.tests.util
-from six.moves import map
-from six.moves import zip
 
 class P(Persistent):
     pass
@@ -108,8 +105,8 @@ class ZODBTests(ZODB.tests.util.TestCase):
         l1.sort()
         l2 = list(ob2.items())
         l2.sort()
-        l1 = map(lambda k_v: (k_v[0], k_v[1][0]), l1)
-        l2 = map(lambda k_v1: (k_v1[0], k_v1[1][0]), l2)
+        l1 = list(map(lambda k_v: (k_v[0], k_v[1][0]), l1))
+        l2 = list(map(lambda k_v1: (k_v1[0], k_v1[1][0]), l2))
         self.assertEqual(l1, l2)
         self.assert_(ob._p_oid != ob2._p_oid)
         self.assertEqual(ob._p_jar, ob2._p_jar)

src/ZODB/tests/test_storage.py

@@ -18,8 +18,6 @@ storage to use for unit tests.  MappingStorage isn't sufficient.
 Since even a minimal storage has some complexity, we run standard
 storage tests against the test storage.
 """
-from __future__ import with_statement
-
 import bisect
 import unittest
 

src/ZODB/tests/testblob.py

@@ -163,13 +163,15 @@ class BlobUndoTests(BlobTestBase):
         root = connection.root()
         transaction.begin()
         blob = Blob()
-        blob.open('w').write('this is state 1')
+        with blob.open('w') as file:
+            file.write('this is state 1')
         root['blob'] = blob
         transaction.commit()
 
         transaction.begin()
         blob = root['blob']
-        blob.open('w').write('this is state 2')
+        with blob.open('w') as file:
+            file.write('this is state 2')
         transaction.commit()
 
 
@@ -184,7 +186,8 @@ class BlobUndoTests(BlobTestBase):
         connection = database.open()
         root = connection.root()
         transaction.begin()
-        open('consume1', 'w').write('this is state 1')
+        with open('consume1', 'w') as file:
+            file.write('this is state 1')
         blob = Blob()
         blob.consumeFile('consume1')
         root['blob'] = blob
@@ -192,7 +195,8 @@ class BlobUndoTests(BlobTestBase):
 
         transaction.begin()
         blob = root['blob']
-        open('consume2', 'w').write('this is state 2')
+        with open('consume2', 'w') as file:
+            file.write('this is state 2')
         blob.consumeFile('consume2')
         transaction.commit()
 
@@ -210,13 +214,15 @@ class BlobUndoTests(BlobTestBase):
         blob = Blob()
 
         transaction.begin()
-        blob.open('w').write('this is state 1')
+        with blob.open('w') as file:
+            file.write('this is state 1')
         root['blob'] = blob
         transaction.commit()
 
         transaction.begin()
         blob = root['blob']
-        blob.open('w').write('this is state 2')
+        with blob.open('w') as file:
+            file.write('this is state 2')
         transaction.commit()
 
         database.undo(database.undoLog(0, 1)[0]['id'])
@@ -238,7 +244,8 @@ class BlobUndoTests(BlobTestBase):
         blob = Blob()
 
         transaction.begin()
-        blob.open('w').write('this is state 1')
+        with blob.open('w') as file:
+            file.write('this is state 1')
         root['blob'] = blob
         transaction.commit()
 
@@ -276,17 +283,20 @@ class RecoveryBlobStorage(BlobTestBase,
         conn.root()[1] = ZODB.blob.Blob()
         transaction.commit()
         conn.root()[2] = ZODB.blob.Blob()
-        conn.root()[2].open('w').write('some data')
+        with conn.root()[2].open('w') as file:
+            file.write('some data')
         transaction.commit()
         conn.root()[3] = ZODB.blob.Blob()
-        conn.root()[3].open('w').write(
-            (''.join(struct.pack(">I", random.randint(0, (1<<32)-1))
-                     for i in range(random.randint(10000,20000)))
-             )[:-random.randint(1,4)]
-            )
+        with conn.root()[3].open('w') as file:
+            file.write(
+                (''.join(struct.pack(">I", random.randint(0, (1<<32)-1))
+                         for i in range(random.randint(10000,20000)))
+                 )[:-random.randint(1,4)]
+                )
         transaction.commit()
         conn.root()[2] = ZODB.blob.Blob()
-        conn.root()[2].open('w').write('some other data')
+        with conn.root()[2].open('w') as file:
+            file.write('some other data')
         transaction.commit()
         self._dst.copyTransactionsFrom(self._storage)
         self.compare(self._storage, self._dst)
@@ -295,7 +305,8 @@ class RecoveryBlobStorage(BlobTestBase,
 def gc_blob_removes_uncommitted_data():
     """
     >>> blob = Blob()
-    >>> blob.open('w').write('x')
+    >>> with blob.open('w') as file:
+    ...     file.write('x')
     >>> fname = blob._p_blob_uncommitted
     >>> os.path.exists(fname)
     True
@@ -330,7 +341,8 @@ def commit_from_wrong_partition():
     >>> root = connection.root()
     >>> from ZODB.blob import Blob
     >>> root['blob'] = Blob()
-    >>> root['blob'].open('w').write('test')
+    >>> with root['blob'].open('w') as file:
+    ...     file.write('test')
     >>> transaction.commit() # doctest: +ELLIPSIS
     Copied blob file ...
 
@@ -340,7 +352,8 @@ def commit_from_wrong_partition():
 Works with savepoints too:
 
     >>> root['blob2'] = Blob()
-    >>> root['blob2'].open('w').write('test2')
+    >>> with root['blob2'].open('w') as file:
+    ...     file.write('test2')
     >>> _ = transaction.savepoint() # doctest: +ELLIPSIS
     Copied blob file ...
 
@@ -379,7 +392,8 @@ def packing_with_uncommitted_data_non_undoing():
     >>> from ZODB.blob import Blob
     >>> root['blob'] = Blob()
     >>> connection.add(root['blob'])
-    >>> root['blob'].open('w').write('test')
+    >>> with root['blob'].open('w') as file:
+    ...     file.write('test')
 
     >>> blob_storage.pack(new_time(), referencesf)
 
@@ -406,7 +420,8 @@ def packing_with_uncommitted_data_undoing():
     >>> from ZODB.blob import Blob
     >>> root['blob'] = Blob()
     >>> connection.add(root['blob'])
-    >>> root['blob'].open('w').write('test')
+    >>> with root['blob'].open('w') as file:
+    ...     file.write('test')
 
     >>> blob_storage.pack(new_time(), referencesf)
 
@@ -478,7 +493,8 @@ def loadblob_tmpstore():
     >>> from ZODB.blob import Blob
     >>> root['blob'] = Blob()
     >>> connection.add(root['blob'])
-    >>> root['blob'].open('w').write('test')
+    >>> with root['blob'].open('w') as file:
+    ...     file.write('test')
     >>> import transaction
     >>> transaction.commit()
     >>> blob_oid = root['blob']._p_oid
@@ -540,7 +556,8 @@ def do_not_depend_on_cwd():
     >>> db = DB(bs)
     >>> conn = db.open()
     >>> conn.root()['blob'] = ZODB.blob.Blob()
-    >>> conn.root()['blob'].open('w').write('data')
+    >>> with conn.root()['blob'].open('w') as file:
+    ...     file.write('data')
     >>> transaction.commit()
     >>> os.chdir(here)
     >>> conn.root()['blob'].open().read()
@@ -557,11 +574,13 @@ def savepoint_isolation():
     >>> conn = db.open()
     >>> conn.root.b = ZODB.blob.Blob('initial')
     >>> transaction.commit()
-    >>> conn.root.b.open('w').write('1')
+    >>> with conn.root.b.open('w') as file:
+    ...     file.write('1')
     >>> _ = transaction.savepoint()
     >>> tm = transaction.TransactionManager()
     >>> conn2 = db.open(transaction_manager=tm)
-    >>> conn2.root.b.open('w').write('2')
+    >>> with conn2.root.b.open('w') as file:
+    ...     file.write('2')
     >>> _ = tm.savepoint()
     >>> conn.root.b.open().read()
     '1'
@@ -585,12 +604,14 @@ def savepoint_commits_without_invalidations_out_of_order():
     >>> conn1 = db.open(transaction_manager=tm1)
     >>> conn1.root.b = ZODB.blob.Blob('initial')
     >>> tm1.commit()
-    >>> conn1.root.b.open('w').write('1')
+    >>> with conn1.root.b.open('w') as file:
+    ...     file.write('1')
     >>> _ = tm1.savepoint()
 
     >>> tm2 = transaction.TransactionManager()
     >>> conn2 = db.open(transaction_manager=tm2)
-    >>> conn2.root.b.open('w').write('2')
+    >>> with conn2.root.b.open('w') as file:
+    ...     file.write('2')
     >>> _ = tm1.savepoint()
     >>> conn1.root.b.open().read()
     '1'
@@ -624,7 +645,8 @@ def savepoint_cleanup():
     []
     >>> conn.root.b = ZODB.blob.Blob('initial')
     >>> transaction.commit()
-    >>> conn.root.b.open('w').write('1')
+    >>> with conn.root.b.open('w') as file:
+    ...     file.write('1')
     >>> _ = transaction.savepoint()
     >>> transaction.abort()
     >>> os.listdir(tdir)

src/ZODB/tests/util.py

@@ -13,9 +13,6 @@
 ##############################################################################
 """Conventience function for creating test databases
 """
-
-from __future__ import with_statement
-
 from ZODB.MappingStorage import DB
 
 import atexit

src/ZODB/utils.py

@@ -78,8 +78,6 @@ def deprecated38(msg):
 
 
 if sys.version_info[0] < 3:
-    bytes = str
-
     def as_bytes(obj):
         "Convert obj into bytes"
         return str(obj)
@@ -93,10 +91,6 @@ if sys.version_info[0] < 3:
     byte_chr = chr
 
 else:
-
-    import builtins
-    bytes = builtins.bytes
-
     def as_bytes(obj):
         if isinstance(obj, bytes):
             # invoking str on a bytes object gives its repr()