cakephp/tests/TestCase/Cache/Engine/MemcachedEngineTest.php

<?php
/**
 * CakePHP(tm) Tests <http://book.cakephp.org/2.0/en/development/testing.html>
 * Copyright (c) Cake Software Foundation, Inc. (http://cakefoundation.org)
 *
 * Licensed under The MIT License
 * For full copyright and license information, please see the LICENSE.txt
 * Redistributions of files must retain the above copyright notice
 *
 * @copyright     Copyright (c) Cake Software Foundation, Inc. (http://cakefoundation.org)
 * @link          http://book.cakephp.org/2.0/en/development/testing.html CakePHP(tm) Tests
 * @since         2.5.0
 * @license       http://www.opensource.org/licenses/mit-license.php MIT License
 */
namespace Cake\Test\TestCase\Cache\Engine;

use Cake\Cache\Cache;
use Cake\Cache\Engine\MemcachedEngine;
use Cake\Core\Configure;
use Cake\TestSuite\TestCase;
use \Memcached;

/**
 * Class TestMemcachedEngine
 *
 */
class TestMemcachedEngine extends MemcachedEngine {

/**
 * public accessor to _parseServerString
 *
 * @param string $server
 * @return array
 */
	public function parseServerString($server) {
		return $this->_parseServerString($server);
	}

	public function setMemcached($memcached) {
		$this->_Memcached = $memcached;
	}

	public function getMemcached() {
		return $this->_Memcached;
	}

}

/**
 * MemcachedEngineTest class
 *
 */
class MemcachedEngineTest extends TestCase {

/**
 * setUp method
 *
 * @return void
 */
	public function setUp() {
		parent::setUp();
		$this->skipIf(!class_exists('Memcached'), 'Memcached is not installed or configured properly.');

		$this->_configCache();
	}

/**
 * Helper method for testing.
 *
 * @param array $config
 * @return void
 */
	protected function _configCache($config = []) {
		$defaults = [
			'className' => 'Memcached',
			'prefix' => 'cake_',
			'duration' => 3600
		];
		Cache::drop('memcached');
		Cache::config('memcached', array_merge($defaults, $config));
	}

/**
 * tearDown method
 *
 * @return void
 */
	public function tearDown() {
		parent::tearDown();
		Cache::drop('memcached');
		Cache::drop('memcached2');
		Cache::drop('memcached_groups');
		Cache::drop('memcached_helper');
		Cache::drop('compressed_memcached');
		Cache::drop('long_memcached');
		Cache::drop('short_memcached');
	}

/**
 * testConfig method
 *
 * @return void
 */
	public function testConfig() {
		$config = Cache::engine('memcached')->config();
		unset($config['path']);
		$expecting = array(
			'prefix' => 'cake_',
			'duration' => 3600,
			'probability' => 100,
			'servers' => array('127.0.0.1'),
			'persistent' => false,
			'compress' => false,
			'login' => null,
			'password' => null,
			'groups' => array(),
			'serialize' => 'php',
			'options' => array()
		);
		$this->assertEquals($expecting, $config);
	}

/**
 * testCompressionSetting method
 *
 * @return void
 */
	public function testCompressionSetting() {
		$Memcached = new TestMemcachedEngine();
		$Memcached->init(array(
			'engine' => 'Memcached',
			'servers' => array('127.0.0.1:11211'),
			'compress' => false
		));

		$this->assertFalse($Memcached->getMemcached()->getOption(\Memcached::OPT_COMPRESSION));

		$MemcachedCompressed = new TestMemcachedEngine();
		$MemcachedCompressed->init(array(
			'engine' => 'Memcached',
			'servers' => array('127.0.0.1:11211'),
			'compress' => true
		));

		$this->assertTrue($MemcachedCompressed->getMemcached()->getOption(\Memcached::OPT_COMPRESSION));
	}

/**
 * test setting options
 *
 * @return void
 */
	public function testOptionsSetting() {
		$memcached = new TestMemcachedEngine();
		$memcached->init(array(
			'engine' => 'Memcached',
			'servers' => array('127.0.0.1:11211'),
			'options' => array(
				Memcached::OPT_BINARY_PROTOCOL => true
			)
		));
		$this->assertEquals(1, $memcached->getMemcached()->getOption(Memcached::OPT_BINARY_PROTOCOL));
	}

/**
 * test accepts only valid serializer engine
 *
 * @return  void
 */
	public function testInvalidSerializerSetting() {
		$Memcached = new TestMemcachedEngine();
		$config = array(
			'className' => 'Memcached',
			'servers' => array('127.0.0.1:11211'),
			'persistent' => false,
			'serialize' => 'invalid_serializer'
		);

		$this->setExpectedException(
			'InvalidArgumentException', 'invalid_serializer is not a valid serializer engine for Memcached'
		);
		$Memcached->init($config);
	}

/**
 * testPhpSerializerSetting method
 *
 * @return void
 */
	public function testPhpSerializerSetting() {
		$Memcached = new TestMemcachedEngine();
		$config = array(
			'className' => 'Memcached',
			'servers' => array('127.0.0.1:11211'),
			'persistent' => false,
			'serialize' => 'php'
		);

		$Memcached->init($config);
		$this->assertEquals(Memcached::SERIALIZER_PHP, $Memcached->getMemcached()->getOption(Memcached::OPT_SERIALIZER));
	}

/**
 * testJsonSerializerSetting method
 *
 * @return void
 */
	public function testJsonSerializerSetting() {
		$this->skipIf(
			!Memcached::HAVE_JSON,
			'Memcached extension is not compiled with json support'
		);

		$Memcached = new TestMemcachedEngine();
		$config = array(
			'engine' => 'Memcached',
			'servers' => array('127.0.0.1:11211'),
			'persistent' => false,
			'serialize' => 'json'
		);

		$Memcached->init($config);
		$this->assertEquals(Memcached::SERIALIZER_JSON, $Memcached->getMemcached()->getOption(Memcached::OPT_SERIALIZER));
	}

/**
 * testIgbinarySerializerSetting method
 *
 * @return void
 */
	public function testIgbinarySerializerSetting() {
		$this->skipIf(
			!Memcached::HAVE_IGBINARY,
			'Memcached extension is not compiled with igbinary support'
		);

		$Memcached = new TestMemcachedEngine();
		$config = array(
			'engine' => 'Memcached',
			'servers' => array('127.0.0.1:11211'),
			'persistent' => false,
			'serialize' => 'igbinary'
		);

		$Memcached->init($config);
		$this->assertEquals(Memcached::SERIALIZER_IGBINARY, $Memcached->getMemcached()->getOption(Memcached::OPT_SERIALIZER));
	}

/**
 * testMsgpackSerializerSetting method
 *
 * @return void
 */
	public function testMsgpackSerializerSetting() {
		$this->skipIf(
			!defined('Memcached::HAVE_MSGPACK') || !Memcached::HAVE_MSGPACK,
			'Memcached extension is not compiled with msgpack support'
		);

		$Memcached = new TestMemcachedEngine();
		$config = array(
			'engine' => 'Memcached',
			'servers' => array('127.0.0.1:11211'),
			'persistent' => false,
			'serialize' => 'msgpack'
		);

		$Memcached->init($config);
		$this->assertEquals(Memcached::SERIALIZER_MSGPACK, $Memcached->getMemcached()->getOption(Memcached::OPT_SERIALIZER));
	}

/**
 * testJsonSerializerThrowException method
 *
 * @return void
 */
	public function testJsonSerializerThrowException() {
		$this->skipIf(
			Memcached::HAVE_JSON,
			'Memcached extension is compiled with json support'
		);

		$Memcached = new TestMemcachedEngine();
		$config = array(
			'className' => 'Memcached',
			'servers' => array('127.0.0.1:11211'),
			'persistent' => false,
			'serialize' => 'json'
		);

		$this->setExpectedException(
			'InvalidArgumentException', 'Memcached extension is not compiled with json support'
		);
		$Memcached->init($config);
	}

/**
 * testMsgpackSerializerThrowException method
 *
 * @return void
 */
	public function testMsgpackSerializerThrowException() {
		$this->skipIf(
			defined('Memcached::HAVE_MSGPACK') && Memcached::HAVE_MSGPACK,
			'Memcached extension is compiled with msgpack support'
		);

		$Memcached = new TestMemcachedEngine();
		$config = array(
			'engine' => 'Memcached',
			'servers' => array('127.0.0.1:11211'),
			'persistent' => false,
			'serialize' => 'msgpack'
		);

		$this->setExpectedException(
			'InvalidArgumentException', 'msgpack is not a valid serializer engine for Memcached'
		);
		$Memcached->init($config);
	}

/**
 * testIgbinarySerializerThrowException method
 *
 * @return void
 */
	public function testIgbinarySerializerThrowException() {
		$this->skipIf(
			Memcached::HAVE_IGBINARY,
			'Memcached extension is compiled with igbinary support'
		);

		$Memcached = new TestMemcachedEngine();
		$config = array(
			'engine' => 'Memcached',
			'servers' => array('127.0.0.1:11211'),
			'persistent' => false,
			'serialize' => 'igbinary'
		);

		$this->setExpectedException(
			'InvalidArgumentException', 'Memcached extension is not compiled with igbinary support'
		);
		$Memcached->init($config);
	}

/**
 * test using authentication without memcached installed with SASL support
 * throw an exception
 *
 * @return void
 */
	public function testSaslAuthException() {
		$MemcachedEngine = new TestMemcachedEngine();
		$config = array(
			'engine' => 'Memcached',
			'servers' => array('127.0.0.1:11211'),
			'persistent' => false,
			'login' => 'test',
			'password' => 'password'
		);

		$Memcached = new Memcached();
		$this->skipIf(
			method_exists($Memcached, 'setSaslAuthData'),
			'Memcached extension is installed with SASL support'
		);

		$this->setExpectedException(
			'InvalidArgumentException', 'Memcached extension is not build with SASL support'
		);
		$MemcachedEngine->init($config);
	}

/**
 * testConfig method
 *
 * @return void
 */
	public function testMultipleServers() {
		$servers = array('127.0.0.1:11211', '127.0.0.1:11222');
		$available = true;
		$Memcached = new \Memcached();

		foreach ($servers as $server) {
			list($host, $port) = explode(':', $server);
			//@codingStandardsIgnoreStart
			if (!$Memcached->addServer($host, $port)) {
				$available = false;
			}
			//@codingStandardsIgnoreEnd
		}

		$this->skipIf(!$available, 'Need memcached servers at ' . implode(', ', $servers) . ' to run this test.');

		$Memcached = new MemcachedEngine();
		$Memcached->init(array('engine' => 'Memcached', 'servers' => $servers));

		$config = $Memcached->config();
		$this->assertEquals($config['servers'], $servers);
		Cache::drop('dual_server');
	}

/**
 * test connecting to an ipv6 server.
 *
 * @return void
 */
	public function testConnectIpv6() {
		$Memcached = new MemcachedEngine();
		$result = $Memcached->init(array(
			'prefix' => 'cake_',
			'duration' => 200,
			'engine' => 'Memcached',
			'servers' => array(
				'[::1]:11211'
			)
		));
		$this->assertTrue($result);
	}

/**
 * test non latin domains.
 *
 * @return void
 */
	public function testParseServerStringNonLatin() {
		$Memcached = new TestMemcachedEngine();
		$result = $Memcached->parseServerString('schülervz.net:13211');
		$this->assertEquals(array('schülervz.net', '13211'), $result);

		$result = $Memcached->parseServerString('sülül:1111');
		$this->assertEquals(array('sülül', '1111'), $result);
	}

/**
 * test unix sockets.
 *
 * @return void
 */
	public function testParseServerStringUnix() {
		$Memcached = new TestMemcachedEngine();
		$result = $Memcached->parseServerString('unix:///path/to/memcachedd.sock');
		$this->assertEquals(array('unix:///path/to/memcachedd.sock', 0), $result);
	}

/**
 * testReadAndWriteCache method
 *
 * @return void
 */
	public function testReadAndWriteCache() {
		$this->_configCache(['duration' => 1]);

		$result = Cache::read('test', 'memcached');
		$expecting = '';
		$this->assertEquals($expecting, $result);

		$data = 'this is a test of the emergency broadcasting system';
		$result = Cache::write('test', $data, 'memcached');
		$this->assertTrue($result);

		$result = Cache::read('test', 'memcached');
		$expecting = $data;
		$this->assertEquals($expecting, $result);

		Cache::delete('test', 'memcached');
	}

/**
 * testReadMany method
 *
 * @return void
 */
	public function testReadMany() {
		$this->_configCache(['duration' => 2]);
		$data = array(
			'App.falseTest' => false,
			'App.trueTest' => true,
			'App.nullTest' => null,
			'App.zeroTest' => 0,
			'App.zeroTest2' => '0'
		);
		foreach ($data as $key => $value) {
			Cache::write($key, $value, 'memcached');
		}

		$read = Cache::readMany(array_merge(array_keys($data), ['App.doesNotExist']), 'memcached');

		$this->assertSame($read['App.falseTest'], false);
		$this->assertSame($read['App.trueTest'], true);
		$this->assertSame($read['App.nullTest'], null);
		$this->assertSame($read['App.zeroTest'], 0);
		$this->assertSame($read['App.zeroTest2'], '0');
		$this->assertSame($read['App.doesNotExist'], false);
	}

/**
 * testWriteMany method
 *
 * @return void
 */
	public function testWriteMany() {
		$this->_configCache(['duration' => 2]);
		$data = array(
			'App.falseTest' => false,
			'App.trueTest' => true,
			'App.nullTest' => null,
			'App.zeroTest' => 0,
			'App.zeroTest2' => '0'
		);
		Cache::writeMany($data, 'memcached');

		$this->assertSame(Cache::read('App.falseTest', 'memcached'), false);
		$this->assertSame(Cache::read('App.trueTest', 'memcached'), true);
		$this->assertSame(Cache::read('App.nullTest', 'memcached'), null);
		$this->assertSame(Cache::read('App.zeroTest', 'memcached'), 0);
		$this->assertSame(Cache::read('App.zeroTest2', 'memcached'), '0');
	}

/**
 * testExpiry method
 *
 * @return void
 */
	public function testExpiry() {
		$this->_configCache(['duration' => 1]);

		$result = Cache::read('test', 'memcached');
		$this->assertFalse($result);

		$data = 'this is a test of the emergency broadcasting system';
		$result = Cache::write('other_test', $data, 'memcached');
		$this->assertTrue($result);

		sleep(2);
		$result = Cache::read('other_test', 'memcached');
		$this->assertFalse($result);

		$this->_configCache(['duration' => '+1 second']);

		$data = 'this is a test of the emergency broadcasting system';
		$result = Cache::write('other_test', $data, 'memcached');
		$this->assertTrue($result);

		sleep(3);
		$result = Cache::read('other_test', 'memcached');
		$this->assertFalse($result);

		$result = Cache::read('other_test', 'memcached');
		$this->assertFalse($result);

		$this->_configCache(['duration' => '+29 days']);
		$data = 'this is a test of the emergency broadcasting system';
		$result = Cache::write('long_expiry_test', $data, 'memcached');
		$this->assertTrue($result);

		sleep(2);
		$result = Cache::read('long_expiry_test', 'memcached');
		$expecting = $data;
		$this->assertEquals($expecting, $result);
	}

/**
 * testDeleteCache method
 *
 * @return void
 */
	public function testDeleteCache() {
		$data = 'this is a test of the emergency broadcasting system';
		$result = Cache::write('delete_test', $data, 'memcached');
		$this->assertTrue($result);

		$result = Cache::delete('delete_test', 'memcached');
		$this->assertTrue($result);
	}

/**
 * testDeleteMany method
 *
 * @return void
 */
	public function testDeleteMany() {
		$this->assertFalse(defined('HHVM_VERSION'), 'Crashes HHVM');
		$this->_configCache();
		$data = array(
			'App.falseTest' => false,
			'App.trueTest' => true,
			'App.nullTest' => null,
			'App.zeroTest' => 0,
			'App.zeroTest2' => '0',
		);
		foreach ($data as $key => $value) {
			Cache::write($key, $value, 'memcached');
		}
		Cache::write('App.keepTest', 'keepMe', 'memcached');

		Cache::deleteMany(array_merge(array_keys($data), ['App.doesNotExist']), 'memcached');

		$this->assertSame(Cache::read('App.falseTest', 'memcached'), false);
		$this->assertSame(Cache::read('App.trueTest', 'memcached'), false);
		$this->assertSame(Cache::read('App.nullTest', 'memcached'), false);
		$this->assertSame(Cache::read('App.zeroTest', 'memcached'), false);
		$this->assertSame(Cache::read('App.zeroTest2', 'memcached'), false);
		$this->assertSame(Cache::read('App.keepTest', 'memcached'), 'keepMe');
	}

/**
 * testDecrement method
 *
 * @return void
 */
	public function testDecrement() {
		$result = Cache::write('test_decrement', 5, 'memcached');
		$this->assertTrue($result);

		$result = Cache::decrement('test_decrement', 1, 'memcached');
		$this->assertEquals(4, $result);

		$result = Cache::read('test_decrement', 'memcached');
		$this->assertEquals(4, $result);

		$result = Cache::decrement('test_decrement', 2, 'memcached');
		$this->assertEquals(2, $result);

		$result = Cache::read('test_decrement', 'memcached');
		$this->assertEquals(2, $result);

		Cache::delete('test_decrement', 'memcached');
	}

/**
 * test decrementing compressed keys
 *
 * @return void
 */
	public function testDecrementCompressedKeys() {
		Cache::config('compressed_memcached', array(
			'engine' => 'Memcached',
			'duration' => '+2 seconds',
			'servers' => array('127.0.0.1:11211'),
			'compress' => true
		));

		$result = Cache::write('test_decrement', 5, 'compressed_memcached');
		$this->assertTrue($result);

		$result = Cache::decrement('test_decrement', 1, 'compressed_memcached');
		$this->assertEquals(4, $result);

		$result = Cache::read('test_decrement', 'compressed_memcached');
		$this->assertEquals(4, $result);

		$result = Cache::decrement('test_decrement', 2, 'compressed_memcached');
		$this->assertEquals(2, $result);

		$result = Cache::read('test_decrement', 'compressed_memcached');
		$this->assertEquals(2, $result);

		Cache::delete('test_decrement', 'compressed_memcached');
	}

/**
 * testIncrement method
 *
 * @return void
 */
	public function testIncrement() {
		$result = Cache::write('test_increment', 5, 'memcached');
		$this->assertTrue($result);

		$result = Cache::increment('test_increment', 1, 'memcached');
		$this->assertEquals(6, $result);

		$result = Cache::read('test_increment', 'memcached');
		$this->assertEquals(6, $result);

		$result = Cache::increment('test_increment', 2, 'memcached');
		$this->assertEquals(8, $result);

		$result = Cache::read('test_increment', 'memcached');
		$this->assertEquals(8, $result);

		Cache::delete('test_increment', 'memcached');
	}

/**
 * test incrementing compressed keys
 *
 * @return void
 */
	public function testIncrementCompressedKeys() {
		Cache::config('compressed_memcached', array(
			'engine' => 'Memcached',
			'duration' => '+2 seconds',
			'servers' => array('127.0.0.1:11211'),
			'compress' => true
		));

		$result = Cache::write('test_increment', 5, 'compressed_memcached');
		$this->assertTrue($result);

		$result = Cache::increment('test_increment', 1, 'compressed_memcached');
		$this->assertEquals(6, $result);

		$result = Cache::read('test_increment', 'compressed_memcached');
		$this->assertEquals(6, $result);

		$result = Cache::increment('test_increment', 2, 'compressed_memcached');
		$this->assertEquals(8, $result);

		$result = Cache::read('test_increment', 'compressed_memcached');
		$this->assertEquals(8, $result);

		Cache::delete('test_increment', 'compressed_memcached');
	}

/**
 * test that configurations don't conflict, when a file engine is declared after a memcached one.
 *
 * @return void
 */
	public function testConfigurationConflict() {
		Cache::config('long_memcached', array(
			'engine' => 'Memcached',
			'duration' => '+2 seconds',
			'servers' => array('127.0.0.1:11211'),
		));
		Cache::config('short_memcached', array(
			'engine' => 'Memcached',
			'duration' => '+1 seconds',
			'servers' => array('127.0.0.1:11211'),
		));

		$this->assertTrue(Cache::write('duration_test', 'yay', 'long_memcached'));
		$this->assertTrue(Cache::write('short_duration_test', 'boo', 'short_memcached'));

		$this->assertEquals('yay', Cache::read('duration_test', 'long_memcached'), 'Value was not read %s');
		$this->assertEquals('boo', Cache::read('short_duration_test', 'short_memcached'), 'Value was not read %s');

		sleep(1);
		$this->assertEquals('yay', Cache::read('duration_test', 'long_memcached'), 'Value was not read %s');

		sleep(2);
		$this->assertFalse(Cache::read('short_duration_test', 'short_memcached'), 'Cache was not invalidated %s');
		$this->assertFalse(Cache::read('duration_test', 'long_memcached'), 'Value did not expire %s');

		Cache::delete('duration_test', 'long_memcached');
		Cache::delete('short_duration_test', 'short_memcached');
	}

/**
 * test clearing memcached.
 *
 * @return void
 */
	public function testClear() {
		$this->assertFalse(defined('HHVM_VERSION'), 'Crashes HHVM');
		Cache::config('memcached2', array(
			'engine' => 'Memcached',
			'prefix' => 'cake2_',
			'duration' => 3600
		));

		Cache::write('some_value', 'cache1', 'memcached');
		$result = Cache::clear(true, 'memcached');
		$this->assertTrue($result);
		$this->assertEquals('cache1', Cache::read('some_value', 'memcached'));

		Cache::write('some_value', 'cache2', 'memcached2');
		$result = Cache::clear(false, 'memcached');
		$this->assertTrue($result);
		$this->assertFalse(Cache::read('some_value', 'memcached'));
		$this->assertEquals('cache2', Cache::read('some_value', 'memcached2'));

		Cache::clear(false, 'memcached2');
	}

/**
 * test that a 0 duration can successfully write.
 *
 * @return void
 */
	public function testZeroDuration() {
		$this->_configCache(['duration' => 0]);
		$result = Cache::write('test_key', 'written!', 'memcached');

		$this->assertTrue($result);
		$result = Cache::read('test_key', 'memcached');
		$this->assertEquals('written!', $result);
	}

/**
 * test that durations greater than 30 days never expire
 *
 * @return void
 */
	public function testLongDurationEqualToZero() {
		$memcached = new TestMemcachedEngine();
		$memcached->init(['prefix' => 'Foo_', 'compress' => false, 'duration' => 50 * DAY]);

		$mock = $this->getMock('Memcached');
		$memcached->setMemcached($mock);
		$mock->expects($this->once())
			->method('set')
			->with('Foo_key', 'value', 0);

		$value = 'value';
		$memcached->write('key', $value);
	}

/**
 * Tests that configuring groups for stored keys return the correct values when read/written
 * Shows that altering the group value is equivalent to deleting all keys under the same
 * group
 *
 * @return void
 */
	public function testGroupReadWrite() {
		Cache::config('memcached_groups', array(
			'engine' => 'Memcached',
			'duration' => 3600,
			'groups' => array('group_a', 'group_b'),
			'prefix' => 'test_'
		));
		Cache::config('memcached_helper', array(
			'engine' => 'Memcached',
			'duration' => 3600,
			'prefix' => 'test_'
		));
		$this->assertTrue(Cache::write('test_groups', 'value', 'memcached_groups'));
		$this->assertEquals('value', Cache::read('test_groups', 'memcached_groups'));

		Cache::increment('group_a', 1, 'memcached_helper');
		$this->assertFalse(Cache::read('test_groups', 'memcached_groups'));
		$this->assertTrue(Cache::write('test_groups', 'value2', 'memcached_groups'));
		$this->assertEquals('value2', Cache::read('test_groups', 'memcached_groups'));

		Cache::increment('group_b', 1, 'memcached_helper');
		$this->assertFalse(Cache::read('test_groups', 'memcached_groups'));
		$this->assertTrue(Cache::write('test_groups', 'value3', 'memcached_groups'));
		$this->assertEquals('value3', Cache::read('test_groups', 'memcached_groups'));
	}

/**
 * Tests that deleteing from a groups-enabled config is possible
 *
 * @return void
 */
	public function testGroupDelete() {
		Cache::config('memcached_groups', array(
			'engine' => 'Memcached',
			'duration' => 3600,
			'groups' => array('group_a', 'group_b')
		));
		$this->assertTrue(Cache::write('test_groups', 'value', 'memcached_groups'));
		$this->assertEquals('value', Cache::read('test_groups', 'memcached_groups'));
		$this->assertTrue(Cache::delete('test_groups', 'memcached_groups'));

		$this->assertFalse(Cache::read('test_groups', 'memcached_groups'));
	}

/**
 * Test clearing a cache group
 *
 * @return void
 */
	public function testGroupClear() {
		Cache::config('memcached_groups', array(
			'engine' => 'Memcached',
			'duration' => 3600,
			'groups' => array('group_a', 'group_b')
		));

		$this->assertTrue(Cache::write('test_groups', 'value', 'memcached_groups'));
		$this->assertTrue(Cache::clearGroup('group_a', 'memcached_groups'));
		$this->assertFalse(Cache::read('test_groups', 'memcached_groups'));

		$this->assertTrue(Cache::write('test_groups', 'value2', 'memcached_groups'));
		$this->assertTrue(Cache::clearGroup('group_b', 'memcached_groups'));
		$this->assertFalse(Cache::read('test_groups', 'memcached_groups'));
	}
}