psycopg2/tests/test_transaction.py
Jon Dufresne fcc083dc12 Always import the system unittest
There is no need to import testutils.unittest instead of simply
unittest. They are simple aliases. Use system unittest to be more
regular, consistent as well as idiomatic with the wider Python
community.
2017-12-01 18:35:30 -08:00

254 lines
9.0 KiB
Python
Executable File

#!/usr/bin/env python
# test_transaction - unit test on transaction behaviour
#
# Copyright (C) 2007-2011 Federico Di Gregorio <fog@debian.org>
#
# psycopg2 is free software: you can redistribute it and/or modify it
# under the terms of the GNU Lesser General Public License as published
# by the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# In addition, as a special exception, the copyright holders give
# permission to link this program with the OpenSSL library (or with
# modified versions of OpenSSL that use the same license as OpenSSL),
# and distribute linked combinations including the two.
#
# You must obey the GNU Lesser General Public License in all respects for
# all of the code used other than OpenSSL.
#
# psycopg2 is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
# FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
# License for more details.
import threading
import unittest
from testutils import ConnectingTestCase, skip_before_postgres, slow
import psycopg2
from psycopg2.extensions import (
ISOLATION_LEVEL_SERIALIZABLE, STATUS_BEGIN, STATUS_READY)
class TransactionTests(ConnectingTestCase):
def setUp(self):
ConnectingTestCase.setUp(self)
self.conn.set_isolation_level(ISOLATION_LEVEL_SERIALIZABLE)
curs = self.conn.cursor()
curs.execute('''
CREATE TEMPORARY TABLE table1 (
id int PRIMARY KEY
)''')
# The constraint is set to deferrable for the commit_failed test
curs.execute('''
CREATE TEMPORARY TABLE table2 (
id int PRIMARY KEY,
table1_id int,
CONSTRAINT table2__table1_id__fk
FOREIGN KEY (table1_id) REFERENCES table1(id) DEFERRABLE)''')
curs.execute('INSERT INTO table1 VALUES (1)')
curs.execute('INSERT INTO table2 VALUES (1, 1)')
self.conn.commit()
def test_rollback(self):
# Test that rollback undoes changes
curs = self.conn.cursor()
curs.execute('INSERT INTO table2 VALUES (2, 1)')
# Rollback takes us from BEGIN state to READY state
self.assertEqual(self.conn.status, STATUS_BEGIN)
self.conn.rollback()
self.assertEqual(self.conn.status, STATUS_READY)
curs.execute('SELECT id, table1_id FROM table2 WHERE id = 2')
self.assertEqual(curs.fetchall(), [])
def test_commit(self):
# Test that commit stores changes
curs = self.conn.cursor()
curs.execute('INSERT INTO table2 VALUES (2, 1)')
# Rollback takes us from BEGIN state to READY state
self.assertEqual(self.conn.status, STATUS_BEGIN)
self.conn.commit()
self.assertEqual(self.conn.status, STATUS_READY)
# Now rollback and show that the new record is still there:
self.conn.rollback()
curs.execute('SELECT id, table1_id FROM table2 WHERE id = 2')
self.assertEqual(curs.fetchall(), [(2, 1)])
def test_failed_commit(self):
# Test that we can recover from a failed commit.
# We use a deferred constraint to cause a failure on commit.
curs = self.conn.cursor()
curs.execute('SET CONSTRAINTS table2__table1_id__fk DEFERRED')
curs.execute('INSERT INTO table2 VALUES (2, 42)')
# The commit should fail, and move the cursor back to READY state
self.assertEqual(self.conn.status, STATUS_BEGIN)
self.assertRaises(psycopg2.IntegrityError, self.conn.commit)
self.assertEqual(self.conn.status, STATUS_READY)
# The connection should be ready to use for the next transaction:
curs.execute('SELECT 1')
self.assertEqual(curs.fetchone()[0], 1)
class DeadlockSerializationTests(ConnectingTestCase):
"""Test deadlock and serialization failure errors."""
def connect(self):
conn = ConnectingTestCase.connect(self)
conn.set_isolation_level(ISOLATION_LEVEL_SERIALIZABLE)
return conn
def setUp(self):
ConnectingTestCase.setUp(self)
curs = self.conn.cursor()
# Drop table if it already exists
try:
curs.execute("DROP TABLE table1")
self.conn.commit()
except psycopg2.DatabaseError:
self.conn.rollback()
try:
curs.execute("DROP TABLE table2")
self.conn.commit()
except psycopg2.DatabaseError:
self.conn.rollback()
# Create sample data
curs.execute("""
CREATE TABLE table1 (
id int PRIMARY KEY,
name text)
""")
curs.execute("INSERT INTO table1 VALUES (1, 'hello')")
curs.execute("CREATE TABLE table2 (id int PRIMARY KEY)")
self.conn.commit()
def tearDown(self):
curs = self.conn.cursor()
curs.execute("DROP TABLE table1")
curs.execute("DROP TABLE table2")
self.conn.commit()
ConnectingTestCase.tearDown(self)
@slow
def test_deadlock(self):
self.thread1_error = self.thread2_error = None
step1 = threading.Event()
step2 = threading.Event()
def task1():
try:
conn = self.connect()
curs = conn.cursor()
curs.execute("LOCK table1 IN ACCESS EXCLUSIVE MODE")
step1.set()
step2.wait()
curs.execute("LOCK table2 IN ACCESS EXCLUSIVE MODE")
except psycopg2.DatabaseError as exc:
self.thread1_error = exc
step1.set()
conn.close()
def task2():
try:
conn = self.connect()
curs = conn.cursor()
step1.wait()
curs.execute("LOCK table2 IN ACCESS EXCLUSIVE MODE")
step2.set()
curs.execute("LOCK table1 IN ACCESS EXCLUSIVE MODE")
except psycopg2.DatabaseError as exc:
self.thread2_error = exc
step2.set()
conn.close()
# Run the threads in parallel. The "step1" and "step2" events
# ensure that the two transactions overlap.
thread1 = threading.Thread(target=task1)
thread2 = threading.Thread(target=task2)
thread1.start()
thread2.start()
thread1.join()
thread2.join()
# Exactly one of the threads should have failed with
# TransactionRollbackError:
self.assertFalse(self.thread1_error and self.thread2_error)
error = self.thread1_error or self.thread2_error
self.assertTrue(isinstance(
error, psycopg2.extensions.TransactionRollbackError))
@slow
def test_serialisation_failure(self):
self.thread1_error = self.thread2_error = None
step1 = threading.Event()
step2 = threading.Event()
def task1():
try:
conn = self.connect()
curs = conn.cursor()
curs.execute("SELECT name FROM table1 WHERE id = 1")
curs.fetchall()
step1.set()
step2.wait()
curs.execute("UPDATE table1 SET name='task1' WHERE id = 1")
conn.commit()
except psycopg2.DatabaseError as exc:
self.thread1_error = exc
step1.set()
conn.close()
def task2():
try:
conn = self.connect()
curs = conn.cursor()
step1.wait()
curs.execute("UPDATE table1 SET name='task2' WHERE id = 1")
conn.commit()
except psycopg2.DatabaseError as exc:
self.thread2_error = exc
step2.set()
conn.close()
# Run the threads in parallel. The "step1" and "step2" events
# ensure that the two transactions overlap.
thread1 = threading.Thread(target=task1)
thread2 = threading.Thread(target=task2)
thread1.start()
thread2.start()
thread1.join()
thread2.join()
# Exactly one of the threads should have failed with
# TransactionRollbackError:
self.assertFalse(self.thread1_error and self.thread2_error)
error = self.thread1_error or self.thread2_error
self.assertTrue(isinstance(
error, psycopg2.extensions.TransactionRollbackError))
class QueryCancellationTests(ConnectingTestCase):
"""Tests for query cancellation."""
def setUp(self):
ConnectingTestCase.setUp(self)
self.conn.set_isolation_level(ISOLATION_LEVEL_SERIALIZABLE)
@skip_before_postgres(8, 2)
def test_statement_timeout(self):
curs = self.conn.cursor()
# Set a low statement timeout, then sleep for a longer period.
curs.execute('SET statement_timeout TO 10')
self.assertRaises(psycopg2.extensions.QueryCanceledError,
curs.execute, 'SELECT pg_sleep(50)')
def test_suite():
return unittest.TestLoader().loadTestsFromName(__name__)
if __name__ == "__main__":
unittest.main()