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#!/usr/bin/python

#

# Copyright (C) 2008 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

# 02110-1301, USA.

"""Script for unittesting the workerpool module"""

import unittest

import threading

import time

import sys

import zlib

from ganeti import workerpool

class DummyBaseWorker(workerpool.BaseWorker):

  def RunTask(self, text):

    pass

class ChecksumContext:

  CHECKSUM_START = zlib.adler32("")

  def __init__(self):

    self.lock = threading.Condition(threading.Lock())

    self.checksum = self.CHECKSUM_START

  @staticmethod

  def UpdateChecksum(current, value):

    return zlib.adler32(str(value), current)

class ChecksumBaseWorker(workerpool.BaseWorker):

  def RunTask(self, ctx, number):

    ctx.lock.acquire()

    try:

      ctx.checksum = ctx.UpdateChecksum(ctx.checksum, number)

    finally:

      ctx.lock.release()

class TestWorkerpool(unittest.TestCase):

  """Workerpool tests"""

  def testDummy(self):

    wp = workerpool.WorkerPool(3, DummyBaseWorker)

    try:

      self._CheckWorkerCount(wp, 3)

      for i in xrange(10):

        wp.AddTask("Hello world %s" % i)

      wp.Quiesce()

    finally:

      wp.TerminateWorkers()

      self._CheckWorkerCount(wp, 0)

  def testNoTasks(self):

    wp = workerpool.WorkerPool(3, DummyBaseWorker)

    try:

      self._CheckWorkerCount(wp, 3)

      self._CheckNoTasks(wp)

    finally:

      wp.TerminateWorkers()

      self._CheckWorkerCount(wp, 0)

  def testNoTasksQuiesce(self):

    wp = workerpool.WorkerPool(3, DummyBaseWorker)

    try:

      self._CheckWorkerCount(wp, 3)

      self._CheckNoTasks(wp)

      wp.Quiesce()

      self._CheckNoTasks(wp)

    finally:

      wp.TerminateWorkers()

      self._CheckWorkerCount(wp, 0)

  def testChecksum(self):

    # Tests whether all tasks are run and, since we're only using a single

    # thread, whether everything is started in order.

    wp = workerpool.WorkerPool(1, ChecksumBaseWorker)

    try:

      self._CheckWorkerCount(wp, 1)

      ctx = ChecksumContext()

      checksum = ChecksumContext.CHECKSUM_START

      for i in xrange(1, 100):

        checksum = ChecksumContext.UpdateChecksum(checksum, i)

        wp.AddTask(ctx, i)

      wp.Quiesce()

      self._CheckNoTasks(wp)

      # Check sum

      ctx.lock.acquire()

      try:

        self.assertEqual(checksum, ctx.checksum)

      finally:

        ctx.lock.release()

    finally:

      wp.TerminateWorkers()

      self._CheckWorkerCount(wp, 0)

  def _CheckNoTasks(self, wp):

    wp._lock.acquire()

    try:

      # The task queue must be empty now

      self.failUnless(not wp._tasks)

    finally:

      wp._lock.release()

  def _CheckWorkerCount(self, wp, num_workers):

    wp._lock.acquire()

    try:

      self.assertEqual(len(wp._workers), num_workers)

    finally:

      wp._lock.release()

if __name__ == '__main__':

  unittest.main()