Synnefo » snf-ganeti

#!/usr/bin/python

#

# Copyright (C) 2006, 2007 Google Inc.

#

# This program is free software; you can redistribute it and/or modify

# it under the terms of the GNU General Public License as published by

# the Free Software Foundation; either version 2 of the License, or

# (at your option) any later version.

#

# This program 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

# General Public License for more details.

#

# You should have received a copy of the GNU General Public License

# along with this program; if not, write to the Free Software

# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA

# 0.0510-1301, USA.

"""Script for unittesting the locking module"""

import os

import unittest

import time

import Queue

from ganeti import locking

from ganeti import errors

from threading import Thread

class TestSharedLock(unittest.TestCase):

  """SharedLock tests"""

  def setUp(self):

    self.sl = locking.SharedLock()

    # helper threads use the 'done' queue to tell the master they finished.

    self.done = Queue.Queue(0)

  def testSequenceAndOwnership(self):

    self.assert_(not self.sl._is_owned())

    self.sl.acquire(shared=1)

    self.assert_(self.sl._is_owned())

    self.assert_(self.sl._is_owned(shared=1))

    self.assert_(not self.sl._is_owned(shared=0))

    self.sl.release()

    self.assert_(not self.sl._is_owned())

    self.sl.acquire()

    self.assert_(self.sl._is_owned())

    self.assert_(not self.sl._is_owned(shared=1))

    self.assert_(self.sl._is_owned(shared=0))

    self.sl.release()

    self.assert_(not self.sl._is_owned())

    self.sl.acquire(shared=1)

    self.assert_(self.sl._is_owned())

    self.assert_(self.sl._is_owned(shared=1))

    self.assert_(not self.sl._is_owned(shared=0))

    self.sl.release()

    self.assert_(not self.sl._is_owned())

  def testBooleanValue(self):

    # semaphores are supposed to return a true value on a successful acquire

    self.assert_(self.sl.acquire(shared=1))

    self.sl.release()

    self.assert_(self.sl.acquire())

    self.sl.release()

  def testDoubleLockingStoE(self):

    self.sl.acquire(shared=1)

    self.assertRaises(AssertionError, self.sl.acquire)

  def testDoubleLockingEtoS(self):

    self.sl.acquire()

    self.assertRaises(AssertionError, self.sl.acquire, shared=1)

  def testDoubleLockingStoS(self):

    self.sl.acquire(shared=1)

    self.assertRaises(AssertionError, self.sl.acquire, shared=1)

  def testDoubleLockingEtoE(self):

    self.sl.acquire()

    self.assertRaises(AssertionError, self.sl.acquire)

  # helper functions: called in a separate thread they acquire the lock, send

  # their identifier on the done queue, then release it.

  def _doItSharer(self):

    try:

      self.sl.acquire(shared=1)

      self.done.put('SHR')

      self.sl.release()

    except errors.LockError:

      self.done.put('ERR')

  def _doItExclusive(self):

    try:

      self.sl.acquire()

      self.done.put('EXC')

      self.sl.release()

    except errors.LockError:

      self.done.put('ERR')

  def _doItDelete(self):

    try:

      self.sl.delete()

      self.done.put('DEL')

    except errors.LockError:

      self.done.put('ERR')

  def testSharersCanCoexist(self):

    self.sl.acquire(shared=1)

    Thread(target=self._doItSharer).start()

    self.assert_(self.done.get(True, 1))

    self.sl.release()

  def testExclusiveBlocksExclusive(self):

    self.sl.acquire()

    Thread(target=self._doItExclusive).start()

    # give it a bit of time to check that it's not actually doing anything

    self.assertRaises(Queue.Empty, self.done.get, True, 0.2)

    self.sl.release()

    self.assert_(self.done.get(True, 1))

  def testExclusiveBlocksDelete(self):

    self.sl.acquire()

    Thread(target=self._doItDelete).start()

    # give it a bit of time to check that it's not actually doing anything

    self.assertRaises(Queue.Empty, self.done.get, True, 0.2)

    self.sl.release()

    self.assert_(self.done.get(True, 1))

  def testExclusiveBlocksSharer(self):

    self.sl.acquire()

    Thread(target=self._doItSharer).start()

    time.sleep(0.05)

    self.assertRaises(Queue.Empty, self.done.get, True, 0.2)

    self.sl.release()

    self.assert_(self.done.get(True, 1))

  def testSharerBlocksExclusive(self):

    self.sl.acquire(shared=1)

    Thread(target=self._doItExclusive).start()

    time.sleep(0.05)

    self.assertRaises(Queue.Empty, self.done.get, True, 0.2)

    self.sl.release()

    self.assert_(self.done.get(True, 1))

  def testSharerBlocksDelete(self):

    self.sl.acquire(shared=1)

    Thread(target=self._doItDelete).start()

    time.sleep(0.05)

    self.assertRaises(Queue.Empty, self.done.get, True, 0.2)

    self.sl.release()

    self.assert_(self.done.get(True, 1))

  def testWaitingExclusiveBlocksSharer(self):

    self.sl.acquire(shared=1)

    # the lock is acquired in shared mode...

    Thread(target=self._doItExclusive).start()

    # ...but now an exclusive is waiting...

    time.sleep(0.05)

    Thread(target=self._doItSharer).start()

    # ...so the sharer should be blocked as well

    self.assertRaises(Queue.Empty, self.done.get, True, 0.2)

    self.sl.release()

    # The exclusive passed before

    self.assertEqual(self.done.get(True, 1), 'EXC')

    self.assertEqual(self.done.get(True, 1), 'SHR')

  def testWaitingSharerBlocksExclusive(self):

    self.sl.acquire()

    # the lock is acquired in exclusive mode...

    Thread(target=self._doItSharer).start()

    # ...but now a sharer is waiting...

    time.sleep(0.05)

    Thread(target=self._doItExclusive).start()

    # ...the exclusive is waiting too...

    self.assertRaises(Queue.Empty, self.done.get, True, 0.2)

    self.sl.release()

    # The sharer passed before

    self.assertEqual(self.done.get(True, 1), 'SHR')

    self.assertEqual(self.done.get(True, 1), 'EXC')

  def testNoNonBlocking(self):

    self.assertRaises(NotImplementedError, self.sl.acquire, blocking=0)

    self.assertRaises(NotImplementedError, self.sl.delete, blocking=0)

    self.sl.acquire()

    self.sl.delete(blocking=0) # Fine, because the lock is already acquired

  def testDelete(self):

    self.sl.delete()

    self.assertRaises(errors.LockError, self.sl.acquire)

    self.assertRaises(errors.LockError, self.sl.acquire, shared=1)

    self.assertRaises(errors.LockError, self.sl.delete)

  def testNoDeleteIfSharer(self):

    self.sl.acquire(shared=1)

    self.assertRaises(AssertionError, self.sl.delete)

  def testDeletePendingSharersExclusiveDelete(self):

    self.sl.acquire()

    Thread(target=self._doItSharer).start()

    Thread(target=self._doItSharer).start()

    time.sleep(0.05)

    Thread(target=self._doItExclusive).start()

    Thread(target=self._doItDelete).start()

    time.sleep(0.05)

    self.sl.delete()

    # The two threads who were pending return both ERR

    self.assertEqual(self.done.get(True, 1), 'ERR')

    self.assertEqual(self.done.get(True, 1), 'ERR')

    self.assertEqual(self.done.get(True, 1), 'ERR')

    self.assertEqual(self.done.get(True, 1), 'ERR')

  def testDeletePendingDeleteExclusiveSharers(self):

    self.sl.acquire()

    Thread(target=self._doItDelete).start()

    Thread(target=self._doItExclusive).start()

    time.sleep(0.05)

    Thread(target=self._doItSharer).start()

    Thread(target=self._doItSharer).start()

    time.sleep(0.05)

    self.sl.delete()

    # The two threads who were pending return both ERR

    self.assertEqual(self.done.get(True, 1), 'ERR')

    self.assertEqual(self.done.get(True, 1), 'ERR')

    self.assertEqual(self.done.get(True, 1), 'ERR')

    self.assertEqual(self.done.get(True, 1), 'ERR')

class TestLockSet(unittest.TestCase):

  """LockSet tests"""

  def setUp(self):

    self.resources = ['one', 'two', 'three']

    self.ls = locking.LockSet(self.resources)

    # helper threads use the 'done' queue to tell the master they finished.

    self.done = Queue.Queue(0)

  def testResources(self):

    self.assertEquals(self.ls._names(), set(self.resources))

    newls = locking.LockSet()

    self.assertEquals(newls._names(), set())

  def testAcquireRelease(self):

    self.ls.acquire('one')

    self.assertEquals(self.ls._list_owned(), set(['one']))

    self.ls.release()

    self.assertEquals(self.ls._list_owned(), set())

    self.ls.acquire(['one'])

    self.assertEquals(self.ls._list_owned(), set(['one']))

    self.ls.release()

    self.assertEquals(self.ls._list_owned(), set())

    self.ls.acquire(['one', 'two', 'three'])

    self.assertEquals(self.ls._list_owned(), set(['one', 'two', 'three']))

    self.ls.release('one')

    self.assertEquals(self.ls._list_owned(), set(['two', 'three']))

    self.ls.release(['three'])

    self.assertEquals(self.ls._list_owned(), set(['two']))

    self.ls.release()

    self.assertEquals(self.ls._list_owned(), set())

    self.ls.acquire(['one', 'three'])

    self.assertEquals(self.ls._list_owned(), set(['one', 'three']))

    self.ls.release()

    self.assertEquals(self.ls._list_owned(), set())

  def testNoDoubleAcquire(self):

    self.ls.acquire('one')

    self.assertRaises(AssertionError, self.ls.acquire, 'one')

    self.assertRaises(AssertionError, self.ls.acquire, ['two'])

    self.assertRaises(AssertionError, self.ls.acquire, ['two', 'three'])

    self.ls.release()

    self.ls.acquire(['one', 'three'])

    self.ls.release('one')

    self.assertRaises(AssertionError, self.ls.acquire, ['two'])

    self.ls.release('three')

  def testNoWrongRelease(self):

    self.assertRaises(AssertionError, self.ls.release)

    self.ls.acquire('one')

    self.assertRaises(AssertionError, self.ls.release, 'two')

  def testAddRemove(self):

    self.ls.add('four')

    self.assertEquals(self.ls._list_owned(), set())

    self.assert_('four' in self.ls._names())

    self.ls.add(['five', 'six', 'seven'], acquired=1)

    self.assert_('five' in self.ls._names())

    self.assert_('six' in self.ls._names())

    self.assert_('seven' in self.ls._names())

    self.assertEquals(self.ls._list_owned(), set(['five', 'six', 'seven']))

    self.ls.remove(['five', 'six'])

    self.assert_('five' not in self.ls._names())

    self.assert_('six' not in self.ls._names())

    self.assertEquals(self.ls._list_owned(), set(['seven']))

    self.ls.add('eight', acquired=1, shared=1)

    self.assert_('eight' in self.ls._names())

    self.assertEquals(self.ls._list_owned(), set(['seven', 'eight']))

    self.ls.remove('seven')

    self.assert_('seven' not in self.ls._names())

    self.assertEquals(self.ls._list_owned(), set(['eight']))

    self.ls.release()

    self.ls.remove(['two'])

    self.assert_('two' not in self.ls._names())

    self.ls.acquire('three')

    self.ls.remove(['three'])

    self.assert_('three' not in self.ls._names())

    self.assertEquals(self.ls.remove('three'), ['three'])

    self.assertEquals(self.ls.remove(['one', 'three', 'six']), ['three', 'six'])

    self.assert_('one' not in self.ls._names())

  def testRemoveNonBlocking(self):

    self.assertRaises(NotImplementedError, self.ls.remove, 'one', blocking=0)

    self.ls.acquire('one')

    self.assertEquals(self.ls.remove('one', blocking=0), [])

    self.ls.acquire(['two', 'three'])

    self.assertEquals(self.ls.remove(['two', 'three'], blocking=0), [])

  def testNoDoubleAdd(self):

    self.assertRaises(errors.LockError, self.ls.add, 'two')

    self.ls.add('four')

    self.assertRaises(errors.LockError, self.ls.add, 'four')

  def testNoWrongRemoves(self):

    self.ls.acquire(['one', 'three'], shared=1)

    # Cannot remove 'two' while holding something which is not a superset

    self.assertRaises(AssertionError, self.ls.remove, 'two')

    # Cannot remove 'three' as we are sharing it

    self.assertRaises(AssertionError, self.ls.remove, 'three')

  def _doLockSet(self, set, shared):

    try:

      self.ls.acquire(set, shared=shared)

      self.done.put('DONE')

      self.ls.release()

    except errors.LockError:

      self.done.put('ERR')

  def _doRemoveSet(self, set):

    self.done.put(self.ls.remove(set))

  def testConcurrentSharedAcquire(self):

    self.ls.acquire(['one', 'two'], shared=1)

    Thread(target=self._doLockSet, args=(['one', 'two'], 1)).start()

    self.assertEqual(self.done.get(True, 1), 'DONE')

    Thread(target=self._doLockSet, args=(['one', 'two', 'three'], 1)).start()

    self.assertEqual(self.done.get(True, 1), 'DONE')

    Thread(target=self._doLockSet, args=('three', 1)).start()

    self.assertEqual(self.done.get(True, 1), 'DONE')

    Thread(target=self._doLockSet, args=(['one', 'two'], 0)).start()

    Thread(target=self._doLockSet, args=(['two', 'three'], 0)).start()

    self.assertRaises(Queue.Empty, self.done.get, True, 0.2)

    self.ls.release()

    self.assertEqual(self.done.get(True, 1), 'DONE')

    self.assertEqual(self.done.get(True, 1), 'DONE')

  def testConcurrentExclusiveAcquire(self):

    self.ls.acquire(['one', 'two'])

    Thread(target=self._doLockSet, args=('three', 1)).start()

    self.assertEqual(self.done.get(True, 1), 'DONE')

    Thread(target=self._doLockSet, args=('three', 0)).start()

    self.assertEqual(self.done.get(True, 1), 'DONE')

    Thread(target=self._doLockSet, args=(['one', 'two'], 0)).start()

    Thread(target=self._doLockSet, args=(['one', 'two'], 1)).start()

    Thread(target=self._doLockSet, args=('one', 0)).start()

    Thread(target=self._doLockSet, args=('one', 1)).start()

    Thread(target=self._doLockSet, args=(['two', 'three'], 0)).start()

    Thread(target=self._doLockSet, args=(['two', 'three'], 1)).start()

    self.assertRaises(Queue.Empty, self.done.get, True, 0.2)

    self.ls.release()

    self.assertEqual(self.done.get(True, 1), 'DONE')

    self.assertEqual(self.done.get(True, 1), 'DONE')

    self.assertEqual(self.done.get(True, 1), 'DONE')

    self.assertEqual(self.done.get(True, 1), 'DONE')

    self.assertEqual(self.done.get(True, 1), 'DONE')

    self.assertEqual(self.done.get(True, 1), 'DONE')

  def testConcurrentRemove(self):

    self.ls.add('four')

    self.ls.acquire(['one', 'two', 'four'])

    Thread(target=self._doLockSet, args=(['one', 'four'], 0)).start()

    Thread(target=self._doLockSet, args=(['one', 'four'], 1)).start()

    Thread(target=self._doLockSet, args=(['one', 'two'], 0)).start()

    Thread(target=self._doLockSet, args=(['one', 'two'], 1)).start()

    self.assertRaises(Queue.Empty, self.done.get, True, 0.2)

    self.ls.remove('one')

    self.ls.release()

    self.assertEqual(self.done.get(True, 1), 'ERR')

    self.assertEqual(self.done.get(True, 1), 'ERR')

    self.assertEqual(self.done.get(True, 1), 'ERR')

    self.assertEqual(self.done.get(True, 1), 'ERR')

    self.ls.add(['five', 'six'], acquired=1)

    Thread(target=self._doLockSet, args=(['three', 'six'], 1)).start()

    Thread(target=self._doLockSet, args=(['three', 'six'], 0)).start()

    Thread(target=self._doLockSet, args=(['four', 'six'], 1)).start()

    Thread(target=self._doLockSet, args=(['four', 'six'], 0)).start()

    self.ls.remove('five')

    self.ls.release()

    self.assertEqual(self.done.get(True, 1), 'DONE')

    self.assertEqual(self.done.get(True, 1), 'DONE')

    self.assertEqual(self.done.get(True, 1), 'DONE')

    self.assertEqual(self.done.get(True, 1), 'DONE')

    self.ls.acquire(['three', 'four'])

    Thread(target=self._doRemoveSet, args=(['four', 'six'], )).start()

    self.assertRaises(Queue.Empty, self.done.get, True, 0.2)

    self.ls.remove('four')

    self.assertEqual(self.done.get(True, 1), ['four'])

    Thread(target=self._doRemoveSet, args=(['two'])).start()

    self.assertEqual(self.done.get(True, 1), [])

    self.ls.release()

class TestGanetiLockManager(unittest.TestCase):

  def setUp(self):

    self.nodes=['n1', 'n2']

    self.instances=['i1', 'i2', 'i3']

    self.GL = locking.GanetiLockManager(nodes=self.nodes,

                                        instances=self.instances)

    self.done = Queue.Queue(0)

  def tearDown(self):

    # Don't try this at home...

    locking.GanetiLockManager._instance = None

  def testLockingConstants(self):

    # The locking library internally cheats by assuming its constants have some

    # relationships with each other. Check those hold true.

    for i in range(len(locking.LEVELS)):

      self.assertEqual(i, locking.LEVELS[i])

  def testDoubleGLFails(self):

    # We are not passing test=True, so instantiating a new one should fail

    self.assertRaises(AssertionError, locking.GanetiLockManager)

  def testLockNames(self):

    self.assertEqual(self.GL._names(locking.LEVEL_CLUSTER), set(['BGL']))

    self.assertEqual(self.GL._names(locking.LEVEL_NODE), set(self.nodes))

    self.assertEqual(self.GL._names(locking.LEVEL_INSTANCE), set(self.instances))

    self.assertEqual(self.GL._names(locking.LEVEL_CONFIG), set(['config']))

  def testInitAndResources(self):

    locking.GanetiLockManager._instance = None

    self.GL = locking.GanetiLockManager()

    self.assertEqual(self.GL._names(locking.LEVEL_CLUSTER), set(['BGL']))

    self.assertEqual(self.GL._names(locking.LEVEL_NODE), set())

    self.assertEqual(self.GL._names(locking.LEVEL_INSTANCE), set())

    self.assertEqual(self.GL._names(locking.LEVEL_CONFIG), set(['config']))

    locking.GanetiLockManager._instance = None

    self.GL = locking.GanetiLockManager(nodes=self.nodes)

    self.assertEqual(self.GL._names(locking.LEVEL_CLUSTER), set(['BGL']))

    self.assertEqual(self.GL._names(locking.LEVEL_NODE), set(self.nodes))

    self.assertEqual(self.GL._names(locking.LEVEL_INSTANCE), set())

    self.assertEqual(self.GL._names(locking.LEVEL_CONFIG), set(['config']))

    locking.GanetiLockManager._instance = None

    self.GL = locking.GanetiLockManager(instances=self.instances)

    self.assertEqual(self.GL._names(locking.LEVEL_CLUSTER), set(['BGL']))

    self.assertEqual(self.GL._names(locking.LEVEL_NODE), set())

    self.assertEqual(self.GL._names(locking.LEVEL_INSTANCE), set(self.instances))

    self.assertEqual(self.GL._names(locking.LEVEL_CONFIG), set(['config']))

  def testAcquireRelease(self):

    self.GL.acquire(locking.LEVEL_CLUSTER, ['BGL'], shared=1)

    self.assertEquals(self.GL._list_owned(locking.LEVEL_CLUSTER), set(['BGL']))

    self.GL.acquire(locking.LEVEL_NODE, ['n1', 'n2'], shared=1)

    self.GL.release(locking.LEVEL_NODE)

    self.GL.acquire(locking.LEVEL_NODE, ['n1'])

    self.assertEquals(self.GL._list_owned(locking.LEVEL_NODE), set(['n1']))

    self.GL.acquire(locking.LEVEL_INSTANCE, ['i1', 'i2'])

    self.GL.acquire(locking.LEVEL_CONFIG, ['config'])

    self.GL.release(locking.LEVEL_INSTANCE, ['i2'])

    self.assertEquals(self.GL._list_owned(locking.LEVEL_INSTANCE), set(['i1']))

    self.GL.release(locking.LEVEL_NODE)

    self.GL.release(locking.LEVEL_INSTANCE)

    self.GL.release(locking.LEVEL_CONFIG)

    self.assertRaises(errors.LockError, self.GL.acquire,

                      locking.LEVEL_INSTANCE, ['i5'])

    self.GL.acquire(locking.LEVEL_INSTANCE, ['i3'], shared=1)

    self.assertEquals(self.GL._list_owned(locking.LEVEL_INSTANCE), set(['i3']))

  def testBGLDependency(self):

    self.assertRaises(AssertionError, self.GL.acquire,

                      locking.LEVEL_NODE, ['n1', 'n2'])

    self.assertRaises(AssertionError, self.GL.acquire,

                      locking.LEVEL_INSTANCE, ['i3'])

    self.GL.acquire(locking.LEVEL_CLUSTER, ['BGL'], shared=1)

    self.GL.acquire(locking.LEVEL_NODE, ['n1'])

    self.assertRaises(AssertionError, self.GL.release,

                      locking.LEVEL_CLUSTER, ['BGL'])

    self.assertRaises(AssertionError, self.GL.release,

                      locking.LEVEL_CLUSTER)

    self.GL.release(locking.LEVEL_NODE)

    self.GL.acquire(locking.LEVEL_INSTANCE, ['i1', 'i2'])

    self.assertRaises(AssertionError, self.GL.release,

                      locking.LEVEL_CLUSTER, ['BGL'])

    self.assertRaises(AssertionError, self.GL.release,

                      locking.LEVEL_CLUSTER)

    self.GL.release(locking.LEVEL_INSTANCE)

    self.GL.acquire(locking.LEVEL_CONFIG, ['config'])

    self.assertRaises(AssertionError, self.GL.release,

                      locking.LEVEL_CLUSTER)

  def testWrongOrder(self):

    self.GL.acquire(locking.LEVEL_CLUSTER, ['BGL'], shared=1)

    self.GL.acquire(locking.LEVEL_INSTANCE, ['i3'])

    self.assertRaises(AssertionError, self.GL.acquire,

                      locking.LEVEL_NODE, ['n1'])

    self.assertRaises(AssertionError, self.GL.acquire,

                      locking.LEVEL_INSTANCE, ['i2'])

    self.GL.acquire(locking.LEVEL_CONFIG, ['config'])

    self.assertRaises(AssertionError, self.GL.acquire,

                      locking.LEVEL_CONFIG, ['config'])

    self.GL.release(locking.LEVEL_INSTANCE)

    self.assertRaises(AssertionError, self.GL.acquire,

                      locking.LEVEL_NODE, ['n1'])

    self.assertRaises(AssertionError, self.GL.acquire,

                      locking.LEVEL_INSTANCE, ['i2'])

    self.assertRaises(AssertionError, self.GL.acquire,

                      locking.LEVEL_CONFIG, ['config'])

  # Helper function to run as a thread that shared the BGL and then acquires

  # some locks at another level.

  def _doLock(self, level, names, shared):

    try:

      self.GL.acquire(locking.LEVEL_CLUSTER, ['BGL'], shared=1)

      self.GL.acquire(level, names, shared=shared)

      self.done.put('DONE')

      self.GL.release(level)

      self.GL.release(locking.LEVEL_CLUSTER)

    except errors.LockError:

      self.done.put('ERR')

  def testConcurrency(self):

    self.GL.acquire(locking.LEVEL_CLUSTER, ['BGL'], shared=1)

    Thread(target=self._doLock, args=(locking.LEVEL_INSTANCE, 'i1', 1)).start()

    self.assertEqual(self.done.get(True, 1), 'DONE')

    self.GL.acquire(locking.LEVEL_NODE, ['n1'])

    self.GL.acquire(locking.LEVEL_INSTANCE, ['i3'])

    self.GL.acquire(locking.LEVEL_CONFIG, ['config'])

    Thread(target=self._doLock, args=(locking.LEVEL_INSTANCE, 'i1', 1)).start()

    self.assertEqual(self.done.get(True, 1), 'DONE')

    Thread(target=self._doLock, args=(locking.LEVEL_INSTANCE, 'i3', 1)).start()

    self.assertRaises(Queue.Empty, self.done.get, True, 0.2)

    self.GL.release(locking.LEVEL_CONFIG)

    self.GL.release(locking.LEVEL_INSTANCE)

    self.assertEqual(self.done.get(True, 1), 'DONE')

    self.GL.acquire(locking.LEVEL_INSTANCE, ['i2'], shared=1)

    Thread(target=self._doLock, args=(locking.LEVEL_INSTANCE, 'i2', 1)).start()

    self.assertEqual(self.done.get(True, 1), 'DONE')

    Thread(target=self._doLock, args=(locking.LEVEL_INSTANCE, 'i2', 0)).start()

    self.assertRaises(Queue.Empty, self.done.get, True, 0.2)

    self.GL.release(locking.LEVEL_INSTANCE)

    self.assertEqual(self.done.get(True, 1), 'DONE')

if __name__ == '__main__':

  unittest.main()

  #suite = unittest.TestLoader().loadTestsFromTestCase(TestSharedLock)

  #unittest.TextTestRunner(verbosity=2).run(suite)