def _zext_supported():
tmpd = mkdtemp('', 'zext_check.')
defer(lambda: rmtree(tmpd))
dbfs = tmpd + '/1.fs'
stor = FileStorage(dbfs, create=True)
db = DB(stor)
conn = db.open()
root = conn.root()
root._p_changed = True
txn = transaction.get()
txn.setExtendedInfo('a', 'b')
txn.commit()
for last_txn in stor.iterator(start=stor.lastTransaction()):
break
else:
assert False, "cannot see details of last transaction"
assert last_txn.extension == {'a': 'b'}
return hasattr(last_txn, 'extension_bytes')
