Removed the extension_bytes feature and updated many tests to use TransactionMetaData

src/ZODB/Connection.py

@@ -49,9 +49,9 @@ from ZODB import utils
 import six
 
 from .mvccadapter import HistoricalStorageAdapter
-from ._compat import dumps, loads, _protocol
 
 from . import valuedoc
+from . import _compat
 
 global_reset_counter = 0
 
@@ -1291,10 +1291,9 @@ class TransactionMetaData:
     def __init__(self, user=u'', description=u'', extension=b''):
         self.user = user
         self.description = description
-        if isinstance(extension, bytes):
-            self.extension_bytes = extension
-        else:
-            self.extension = extension
+        if not isinstance(extension, dict):
+            extension = _compat.loads(extension) if extension else {}
+        self.extension = extension
 
     @property
     def user(self):
@@ -1316,6 +1315,16 @@ class TransactionMetaData:
             description = description.encode('utf-8')
         self.__description = description
 
+    def note(self, text): # for tests
+        text = text.strip()
+        if not isinstance(text, bytes):
+            text = text.encode('utf-8')
+        if self.description:
+            self.description = self.description.strip() + b' ' + text
+        else:
+            self.description = text
+
+
     @property
     def extension(self):
         return self.__extension
@@ -1323,16 +1332,5 @@ class TransactionMetaData:
     @extension.setter
     def extension(self, v):
         self.__extension = v
-        self.__extension_bytes = dumps(v, _protocol) if v else b''
 
     _extension = extension
-
-    @property
-    def extension_bytes(self):
-        return self.__extension_bytes
-
-    @extension_bytes.setter
-    def extension_bytes(self, v):
-        d = loads(v) if v else {}
-        self.__extension_bytes = v if d else b''
-        self.__extension = d

src/ZODB/tests/BasicStorage.py

@@ -19,12 +19,12 @@ http://www.zope.org/Documentation/Developer/Models/ZODB/ZODB_Architecture_Storag
 All storages should be able to pass these tests.
 """
 from ZODB import POSException
+from ZODB.Connection import TransactionMetaData
 from ZODB.tests.MinPO import MinPO
 from ZODB.tests.StorageTestBase import zodb_unpickle, zodb_pickle
 
 import threading
 import time
-import transaction
 import zope.interface
 import zope.interface.verify
 
@@ -36,7 +36,7 @@ class BasicStorage:
     def checkBasics(self):
         self.assertEqual(self._storage.lastTransaction(), ZERO)
 
-        t = transaction.Transaction()
+        t = TransactionMetaData()
         self._storage.tpc_begin(t)
         self.assertRaises(POSException.StorageTransactionError,
                           self._storage.tpc_begin, t)
@@ -48,22 +48,22 @@ class BasicStorage:
         self.assertRaises(
             POSException.StorageTransactionError,
             self._storage.store,
-            ZERO, ZERO, b'', '', transaction.Transaction())
+            ZERO, ZERO, b'', '', TransactionMetaData())
 
         self.assertRaises(
             POSException.StorageTransactionError,
             self._storage.store,
-            ZERO, 1, b'2', '', transaction.Transaction())
+            ZERO, 1, b'2', '', TransactionMetaData())
 
         self.assertRaises(
             POSException.StorageTransactionError,
-            self._storage.tpc_vote, transaction.Transaction())
+            self._storage.tpc_vote, TransactionMetaData())
         self._storage.tpc_abort(t)
 
     def checkSerialIsNoneForInitialRevision(self):
         eq = self.assertEqual
         oid = self._storage.new_oid()
-        txn = transaction.Transaction()
+        txn = TransactionMetaData()
         self._storage.tpc_begin(txn)
         # Use None for serial.  Don't use _dostore() here because that coerces
         # serial=None to serial=ZERO.
@@ -106,7 +106,7 @@ class BasicStorage:
 
     def checkWriteAfterAbort(self):
         oid = self._storage.new_oid()
-        t = transaction.Transaction()
+        t = TransactionMetaData()
         self._storage.tpc_begin(t)
         self._storage.store(oid, ZERO, zodb_pickle(MinPO(5)), '', t)
         # Now abort this transaction
@@ -119,7 +119,7 @@ class BasicStorage:
         oid1 = self._storage.new_oid()
         revid1 = self._dostore(oid=oid1, data=MinPO(-2))
         oid = self._storage.new_oid()
-        t = transaction.Transaction()
+        t = TransactionMetaData()
         self._storage.tpc_begin(t)
         self._storage.store(oid, ZERO, zodb_pickle(MinPO(5)), '', t)
         # Now abort this transaction
@@ -180,7 +180,7 @@ class BasicStorage:
 
     def checkNote(self):
         oid = self._storage.new_oid()
-        t = transaction.Transaction()
+        t = TransactionMetaData()
         self._storage.tpc_begin(t)
         t.note('this is a test')
         self._storage.store(oid, ZERO, zodb_pickle(MinPO(5)), '', t)
@@ -194,18 +194,14 @@ class BasicStorage:
     def checkMultipleEmptyTransactions(self):
         # There was a bug in handling empty transactions in mapping
         # storage that caused the commit lock not to be released. :(
-        transaction.begin()
-        t = transaction.get()
+        t = TransactionMetaData()
         self._storage.tpc_begin(t)
         self._storage.tpc_vote(t)
         self._storage.tpc_finish(t)
-        t.commit()
-        transaction.begin()
-        t = transaction.get()
+        t = TransactionMetaData()
         self._storage.tpc_begin(t)      # Hung here before
         self._storage.tpc_vote(t)
         self._storage.tpc_finish(t)
-        t.commit()
 
     def _do_store_in_separate_thread(self, oid, revid, voted):
         # We'll run the competing trans in a separate thread:
@@ -224,8 +220,7 @@ class BasicStorage:
 
         #----------------------------------------------------------------------
         # stale read
-        transaction.begin()
-        t = transaction.get()
+        t = TransactionMetaData()
         self._storage.tpc_begin(t)
         try:
             self._storage.store(b'\0\0\0\0\0\0\0\xf1',
@@ -243,8 +238,7 @@ class BasicStorage:
 
         #----------------------------------------------------------------------
         # non-stale read, no stress. :)
-        transaction.begin()
-        t = transaction.get()
+        t = TransactionMetaData()
         self._storage.tpc_begin(t)
         self._storage.store(b'\0\0\0\0\0\0\0\xf2',
                             b'\0\0\0\0\0\0\0\0', data, '', t)
@@ -255,8 +249,7 @@ class BasicStorage:
         #----------------------------------------------------------------------
         # non-stale read, competition after vote.  The competing
         # transaction must produce a tid > this transaction's tid
-        transaction.begin()
-        t = transaction.get()
+        t = TransactionMetaData()
         self._storage.tpc_begin(t)
         self._storage.store(b'\0\0\0\0\0\0\0\xf3',
                             b'\0\0\0\0\0\0\0\0', data, '', t)
@@ -275,8 +268,7 @@ class BasicStorage:
 
         #----------------------------------------------------------------------
         # non-stale competing trans after checkCurrentSerialInTransaction
-        transaction.begin()
-        t = transaction.get()
+        t = TransactionMetaData()
         self._storage.tpc_begin(t)
         self._storage.store(b'\0\0\0\0\0\0\0\xf4',
                             b'\0\0\0\0\0\0\0\0', data, '', t)
@@ -312,7 +304,7 @@ class BasicStorage:
         # verify that a storage gets it right.
 
         # First, some initial data.
-        t = transaction.get()
+        t = TransactionMetaData()
         self._storage.tpc_begin(t)
         self._storage.store(ZERO, ZERO, b'x', '', t)
         self._storage.tpc_vote(t)
@@ -322,7 +314,7 @@ class BasicStorage:
         # OK, now we'll start a new transaction, take it to finish,
         # and then block finish while we do some other operations.
 
-        t = transaction.get()
+        t = TransactionMetaData()
         self._storage.tpc_begin(t)
         self._storage.store(ZERO, tids[0], b'y', '', t)
         self._storage.tpc_vote(t)

src/ZODB/tests/ConflictResolution.py

@@ -14,9 +14,10 @@
 """Tests for application-level conflict resolution."""
 
 from ZODB import DB
+from ZODB.Connection import TransactionMetaData
 from ZODB.POSException import ConflictError, UndoError
 from persistent import Persistent
-from transaction import Transaction, TransactionManager
+from transaction import TransactionManager
 
 from ZODB.tests.StorageTestBase import zodb_unpickle, zodb_pickle
 
@@ -148,7 +149,7 @@ class ConflictResolvingTransUndoStorage:
         # Start the undo
         info = self._storage.undoInfo()
         tid = info[1]['id']
-        t = Transaction()
+        t = TransactionMetaData()
         self._storage.tpc_begin(t)
         self._storage.undo(tid, t)
         self._storage.tpc_vote(t)
@@ -170,6 +171,6 @@ class ConflictResolvingTransUndoStorage:
         # Start the undo
         info = self._storage.undoInfo()
         tid = info[1]['id']
-        t = Transaction()
+        t = TransactionMetaData()
         self.assertRaises(UndoError, self._begin_undos_vote, t, tid)
         self._storage.tpc_abort(t)

src/ZODB/tests/IteratorStorage.py

@@ -18,12 +18,11 @@ all these tests.
 
 """
 
+from ZODB.Connection import TransactionMetaData
 from ZODB.tests.MinPO import MinPO
 from ZODB.tests.StorageTestBase import zodb_pickle, zodb_unpickle
 from ZODB.utils import U64, p64, load_current
 
-from transaction import Transaction
-
 import ZODB.blob
 
 try:
@@ -67,7 +66,7 @@ class IteratorStorage(IteratorCompare):
         info = self._storage.undoInfo()
         tid = info[0]['id']
         # Undo the creation of the object, rendering it a zombie
-        t = Transaction()
+        t = TransactionMetaData()
         self._storage.tpc_begin(t)
         oids = self._storage.undo(tid, t)
         self._storage.tpc_vote(t)
@@ -105,7 +104,7 @@ class IteratorStorage(IteratorCompare):
         # Then the code in FileIterator.next() hasn't yet been fixed.
         # Should automate that check.
         oid = self._storage.new_oid()
-        t = Transaction()
+        t = TransactionMetaData()
         data = zodb_pickle(MinPO(0))
         try:
             self._storage.tpc_begin(t)

src/ZODB/tests/MTStorage.py

@@ -8,6 +8,7 @@ import six
 import transaction
 
 import ZODB
+from ZODB.Connection import TransactionMetaData
 from ZODB.tests.StorageTestBase import zodb_pickle, zodb_unpickle
 from ZODB.tests.MinPO import MinPO
 from ZODB.POSException import ConflictError
@@ -140,7 +141,7 @@ class StorageClientThread(TestThread):
 
     def dostore(self, i):
         data = zodb_pickle(MinPO((self.getName(), i)))
-        t = transaction.Transaction()
+        t = TransactionMetaData()
         oid = self.oid()
         self.pause()
 

src/ZODB/tests/ReadOnlyStorage.py

@@ -11,8 +11,8 @@
 # FOR A PARTICULAR PURPOSE.
 #
 ##############################################################################
+from ZODB.Connection import TransactionMetaData
 from ZODB.POSException import ReadOnlyError, Unsupported
-import transaction
 
 from ZODB.utils import load_current
 
@@ -48,7 +48,7 @@ class ReadOnlyStorage:
     def checkWriteMethods(self):
         self._make_readonly()
         self.assertRaises(ReadOnlyError, self._storage.new_oid)
-        t = transaction.Transaction()
+        t = TransactionMetaData()
         self.assertRaises(ReadOnlyError, self._storage.tpc_begin, t)
 
         self.assertRaises(ReadOnlyError, self._storage.store,

src/ZODB/tests/RecoveryStorage.py

@@ -14,7 +14,7 @@
 """More recovery and iterator tests."""
 
 import transaction
-from transaction import Transaction
+from ZODB.Connection import TransactionMetaData
 from ZODB.tests.IteratorStorage import IteratorDeepCompare
 from ZODB.tests.StorageTestBase import MinPO, snooze
 from ZODB import DB
@@ -147,7 +147,7 @@ class RecoveryStorage(IteratorDeepCompare):
         # Undo the attribute creation.
         info = self._storage.undoInfo()
         tid = info[0]['id']
-        t = Transaction()
+        t = TransactionMetaData()
         self._storage.tpc_begin(t)
         oids = self._storage.undo(tid, t)
         self._storage.tpc_vote(t)
@@ -171,7 +171,7 @@ class RecoveryStorage(IteratorDeepCompare):
         # Undo the undo (restore the attributes).
         info = self._storage.undoInfo()
         tid = info[0]['id']
-        t = Transaction()
+        t = TransactionMetaData()
         self._storage.tpc_begin(t)
         oids = self._storage.undo(tid, t)
         self._storage.tpc_vote(t)

src/ZODB/tests/RevisionStorage.py

@@ -13,12 +13,11 @@
 ##############################################################################
 """Check loadSerial() on storages that support historical revisions."""
 
+from ZODB.Connection import TransactionMetaData
 from ZODB.tests.MinPO import MinPO
 from ZODB.tests.StorageTestBase import zodb_unpickle, zodb_pickle, snooze
 from ZODB.utils import p64, u64, load_current
 
-import transaction
-
 ZERO = '\0'*8
 
 class RevisionStorage:
@@ -142,7 +141,7 @@ class RevisionStorage:
         oid = self._storage.new_oid()
         def helper(tid, revid, x):
             data = zodb_pickle(MinPO(x))
-            t = transaction.Transaction()
+            t = TransactionMetaData()
             try:
                 self._storage.tpc_begin(t, p64(tid))
                 self._storage.store(oid, revid, data, '', t)

src/ZODB/tests/StorageTestBase.py

@@ -21,8 +21,8 @@ single object revision.
 from __future__ import print_function
 import sys
 import time
-import transaction
 
+from ZODB.Connection import TransactionMetaData
 from ZODB.utils import u64, z64
 from ZODB.tests.MinPO import MinPO
 from ZODB._compat import PersistentPickler, Unpickler, BytesIO, _protocol
@@ -144,7 +144,7 @@ class StorageTestBase(ZODB.tests.util.TestCase):
         if not already_pickled:
             data = zodb_pickle(data)
         # Begin the transaction
-        t = transaction.Transaction()
+        t = TransactionMetaData()
         if user is not None:
             t.user = user
         if description is not None:
@@ -170,7 +170,7 @@ class StorageTestBase(ZODB.tests.util.TestCase):
     def _undo(self, tid, expected_oids=None, note=None):
         # Undo a tid that affects a single object (oid).
         # This is very specialized.
-        t = transaction.Transaction()
+        t = TransactionMetaData()
         t.note(note or "undo")
         self._storage.tpc_begin(t)
         undo_result = self._storage.undo(tid, t)

src/ZODB/tests/Synchronization.py

@@ -62,7 +62,7 @@ tested?  Is it a general restriction?
 
 """
 
-from transaction import Transaction
+from ZODB.Connection import TransactionMetaData
 from ZODB.POSException import StorageTransactionError
 
 OID = "\000" * 8
@@ -75,43 +75,43 @@ class SynchronizedStorage:
         self.assertRaises(StorageTransactionError, callable, *args)
 
     def verifyWrongTrans(self, callable, *args):
-        t = Transaction()
+        t = TransactionMetaData()
         self._storage.tpc_begin(t)
         self.assertRaises(StorageTransactionError, callable, *args)
         self._storage.tpc_abort(t)
 
     def checkStoreNotCommitting(self):
         self.verifyNotCommitting(self._storage.store,
-                                 OID, SERIALNO, b"", "", Transaction())
+                                 OID, SERIALNO, b"", "", TransactionMetaData())
 
     def checkStoreWrongTrans(self):
         self.verifyWrongTrans(self._storage.store,
-                              OID, SERIALNO, b"", "", Transaction())
+                              OID, SERIALNO, b"", "", TransactionMetaData())
 
     def checkAbortNotCommitting(self):
-        self._storage.tpc_abort(Transaction())
+        self._storage.tpc_abort(TransactionMetaData())
 
     def checkAbortWrongTrans(self):
-        t = Transaction()
+        t = TransactionMetaData()
         self._storage.tpc_begin(t)
-        self._storage.tpc_abort(Transaction())
+        self._storage.tpc_abort(TransactionMetaData())
         self._storage.tpc_abort(t)
 
     def checkFinishNotCommitting(self):
-        t = Transaction()
+        t = TransactionMetaData()
         self.assertRaises(StorageTransactionError,
                           self._storage.tpc_finish, t)
         self._storage.tpc_abort(t)
 
     def checkFinishWrongTrans(self):
-        t = Transaction()
+        t = TransactionMetaData()
         self._storage.tpc_begin(t)
         self.assertRaises(StorageTransactionError,
-                          self._storage.tpc_finish, Transaction())
+                          self._storage.tpc_finish, TransactionMetaData())
         self._storage.tpc_abort(t)
 
     def checkBeginCommitting(self):
-        t = Transaction()
+        t = TransactionMetaData()
         self._storage.tpc_begin(t)
         self._storage.tpc_abort(t)
 

src/ZODB/tests/TransactionalUndoStorage.py

@@ -22,6 +22,7 @@ import transaction
 from transaction import Transaction
 
 from ZODB import POSException
+from ZODB.Connection import TransactionMetaData
 from ZODB.serialize import referencesf
 from ZODB.utils import p64, load_current
 from ZODB import DB
@@ -53,7 +54,7 @@ def listeq(L1, L2):
 class TransactionalUndoStorage:
 
     def _multi_obj_transaction(self, objs):
-        t = Transaction()
+        t = TransactionMetaData()
         self._storage.tpc_begin(t)
         for oid, rev, data in objs:
             self._storage.store(oid, rev, data, '', t)
@@ -82,7 +83,7 @@ class TransactionalUndoStorage:
         return oids
 
     def undo(self, tid, note=None):
-        t = Transaction()
+        t = TransactionMetaData()
         if note is not None:
             t.note(note)
         oids = self._begin_undos_vote(t, tid)
@@ -182,7 +183,7 @@ class TransactionalUndoStorage:
         oid2 = self._storage.new_oid()
         revid1 = revid2 = ZERO
         # Store two objects in the same transaction
-        t = Transaction()
+        t = TransactionMetaData()
         self._storage.tpc_begin(t)
         self._storage.store(oid1, revid1, p31, '', t)
         self._storage.store(oid2, revid2, p51, '', t)
@@ -190,7 +191,7 @@ class TransactionalUndoStorage:
         self._storage.tpc_vote(t)
         tid = self._storage.tpc_finish(t)
         # Update those same two objects
-        t = Transaction()
+        t = TransactionMetaData()
         self._storage.tpc_begin(t)
         self._storage.store(oid1, tid, p32, '', t)
         self._storage.store(oid2, tid, p52, '', t)
@@ -242,7 +243,7 @@ class TransactionalUndoStorage:
         info = self._storage.undoInfo()
         tid = info[0]['id']
         tid1 = info[1]['id']
-        t = Transaction()
+        t = TransactionMetaData()
         oids = self._begin_undos_vote(t, tid, tid1)
         serial = self._storage.tpc_finish(t)
         # We may get the finalization stuff called an extra time,
@@ -275,7 +276,7 @@ class TransactionalUndoStorage:
         revid1 = self._dostore(oid1, data=p31, already_pickled=1)
         revid2 = self._dostore(oid2, data=p51, already_pickled=1)
         # Update those same two objects
-        t = Transaction()
+        t = TransactionMetaData()
         self._storage.tpc_begin(t)
         self._storage.store(oid1, revid1, p32, '', t)
         self._storage.store(oid2, revid2, p52, '', t)
@@ -291,7 +292,7 @@ class TransactionalUndoStorage:
         eq(zodb_unpickle(data), MinPO(51))
         # Like the above, but this time, the second transaction contains only
         # one object.
-        t = Transaction()
+        t = TransactionMetaData()
         self._storage.tpc_begin(t)
         self._storage.store(oid1, revid1, p33, '', t)
         self._storage.store(oid2, revid2, p53, '', t)
@@ -320,7 +321,7 @@ class TransactionalUndoStorage:
         # Start the undo
         info = self._storage.undoInfo()
         tid = info[1]['id']
-        t = Transaction()
+        t = TransactionMetaData()
         self.assertRaises(POSException.UndoError,
                           self._begin_undos_vote, t, tid)
         self._storage.tpc_abort(t)
@@ -334,7 +335,7 @@ class TransactionalUndoStorage:
         p81, p82, p91, p92 = map(zodb_pickle,
                                  map(MinPO, (81, 82, 91, 92)))
 
-        t = Transaction()
+        t = TransactionMetaData()
         self._storage.tpc_begin(t)
         self._storage.store(oid1, revid1, p81, '', t)
         self._storage.store(oid2, revid2, p91, '', t)
@@ -352,7 +353,7 @@ class TransactionalUndoStorage:
         self.assertNotEqual(tid, revid2)
         info = self._storage.undoInfo()
         tid = info[1]['id']
-        t = Transaction()
+        t = TransactionMetaData()
         self.assertRaises(POSException.UndoError,
                           self._begin_undos_vote, t, tid)
         self._storage.tpc_abort(t)
@@ -570,7 +571,7 @@ class TransactionalUndoStorage:
 
         orig = []
         for i in range(BATCHES):
-            t = Transaction()
+            t = TransactionMetaData()
             tid = p64(i + 1)
             s.tpc_begin(t, tid)
             for j in range(OBJECTS):
@@ -593,7 +594,7 @@ class TransactionalUndoStorage:
 
         def undo(i):
             info = s.undoInfo()
-            t = Transaction()
+            t = TransactionMetaData()
             s.tpc_begin(t)
             base = i * OBJECTS + i
             for j in range(OBJECTS):

src/ZODB/tests/testFileStorage.py

@@ -24,6 +24,7 @@ import ZODB.tests.testblob
 import zope.testing.setupstack
 from ZODB import POSException
 from ZODB import DB
+from ZODB.Connection import TransactionMetaData
 from ZODB.fsIndex import fsIndex
 from ZODB.utils import U64, p64, z64, load_current
 
@@ -182,7 +183,7 @@ class FileStorageTests(
         # If .store() is handed an oid bigger than the storage knows
         # about already, it's crucial that the storage bump its notion
         # of the largest oid in use.
-        t = transaction.Transaction()
+        t = TransactionMetaData()
         self._storage.tpc_begin(t)
         giant_oid = b'\xee' * 8
         # Store an object.
@@ -199,7 +200,7 @@ class FileStorageTests(
         # knows about already, it's crucial that the storage bump its notion
         # of the largest oid in use.  Because copyTransactionsFrom(), and
         # ZRS recovery, use the .restore() method, this is plain critical.
-        t = transaction.Transaction()
+        t = TransactionMetaData()
         self._storage.tpc_begin(t)
         giant_oid = b'\xee' * 8
         # Store an object.
@@ -289,7 +290,7 @@ class FileStorageTests(
     def checkFlushAfterTruncate(self, fail=False):
         r0 = self._dostore(z64)
         storage = self._storage
-        t = transaction.Transaction()
+        t = TransactionMetaData()
         storage.tpc_begin(t)
         storage.store(z64, r0, b'foo', b'', t)
         storage.tpc_vote(t)
@@ -421,7 +422,7 @@ class AnalyzeDotPyTest(StorageTestBase.StorageTestBase):
             self._storage.store(oid, revid, data, "", t)
 
         for i in range(2):
-            t = transaction.Transaction()
+            t = TransactionMetaData()
             self._storage.tpc_begin(t)
 
             # sometimes data is in this format

src/ZODB/tests/testMVCCMappingStorage.py

@@ -16,6 +16,7 @@ import unittest
 
 from persistent.mapping import PersistentMapping
 import transaction
+from ZODB.Connection import TransactionMetaData
 from ZODB.DB import DB
 from ZODB.tests.MVCCMappingStorage import MVCCMappingStorage
 import ZODB.blob
@@ -161,7 +162,7 @@ class MVCCMappingStorageTests(
         import time
         from ZODB.utils import newTid
         from ZODB.TimeStamp import TimeStamp
-        t = transaction.Transaction()
+        t = TransactionMetaData()
         self._storage.tpc_begin(t)
         self._storage.tpc_vote(t)
         self._storage.tpc_finish(t)
@@ -173,7 +174,7 @@ class MVCCMappingStorageTests(
         transactions[fake_timestamp] = transactions.values()[0]
 
         # Verify the next transaction comes after the fake transaction
-        t = transaction.Transaction()
+        t = TransactionMetaData()
         self._storage.tpc_begin(t)
         self.assertEqual(self._storage._tid, b'zzzzzzzz')
 

src/ZODB/tests/testPersistentMapping.py

@@ -23,9 +23,8 @@ old code, developers will have a hard time testing the new code.
 import unittest
 import sys
 
-from transaction import Transaction
-
 import ZODB
+from ZODB.Connection import TransactionMetaData
 from ZODB.MappingStorage import MappingStorage
 
 from six import PY2
@@ -47,7 +46,7 @@ class PMTests(unittest.TestCase):
             return
         # insert the pickle in place of the root
         s = MappingStorage()
-        t = Transaction()
+        t = TransactionMetaData()
         s.tpc_begin(t)
         s.store('\000' * 8, None, pickle, '', t)
         s.tpc_vote(t)