Merge "Chinese Conversion Table Update 2017-6"
[lhc/web/wiklou.git] / tests / phpunit / includes / libs / objectcache / WANObjectCacheTest.php
index b779231..7053fc1 100644 (file)
@@ -17,7 +17,10 @@ use Wikimedia\TestingAccessWrapper;
  * @covers WANObjectCache::setInterimValue
  */
 class WANObjectCacheTest extends PHPUnit_Framework_TestCase {
-       /** @var WANObjectCache */
+
+       use MediaWikiCoversValidator;
+
+       /** @var TimeAdjustableWANObjectCache */
        private $cache;
        /** @var BagOStuff */
        private $internalCache;
@@ -25,8 +28,8 @@ class WANObjectCacheTest extends PHPUnit_Framework_TestCase {
        protected function setUp() {
                parent::setUp();
 
-               $this->cache = new WANObjectCache( [
-                       'cache' => new HashBagOStuff(),
+               $this->cache = new TimeAdjustableWANObjectCache( [
+                       'cache' => new TimeAdjustableHashBagOStuff(),
                        'pool' => 'testcache-hash',
                        'relayer' => new EventRelayerNull( [] )
                ] );
@@ -215,15 +218,16 @@ class WANObjectCacheTest extends PHPUnit_Framework_TestCase {
                $this->assertGreaterThanOrEqual( 19, $curTTL, 'Current TTL between 19-20 (overriden)' );
 
                $wasSet = 0;
-               $v = $cache->getWithSetCallback( $key, 30, $func, [
-                               'lowTTL' => 0,
-                               'lockTSE' => 5,
-                       ] + $extOpts );
+               $v = $cache->getWithSetCallback(
+                       $key, 30, $func, [ 'lowTTL' => 0, 'lockTSE' => 5 ] + $extOpts );
                $this->assertEquals( $value, $v, "Value returned" );
                $this->assertEquals( 0, $wasSet, "Value not regenerated" );
 
-               $priorTime = microtime( true );
-               usleep( 1 );
+               $priorTime = microtime( true ); // reference time
+               $cache->setTime( $priorTime );
+
+               $cache->addTime( 1 );
+
                $wasSet = 0;
                $v = $cache->getWithSetCallback(
                        $key, 30, $func, [ 'checkKeys' => [ $cKey1, $cKey2 ] ] + $extOpts
@@ -237,7 +241,8 @@ class WANObjectCacheTest extends PHPUnit_Framework_TestCase {
                $t2 = $cache->getCheckKeyTime( $cKey2 );
                $this->assertGreaterThanOrEqual( $priorTime, $t2, 'Check keys generated on miss' );
 
-               $priorTime = microtime( true );
+               $priorTime = $cache->addTime( 0.01 );
+
                $wasSet = 0;
                $v = $cache->getWithSetCallback(
                        $key, 30, $func, [ 'checkKeys' => [ $cKey1, $cKey2 ] ] + $extOpts
@@ -267,11 +272,6 @@ class WANObjectCacheTest extends PHPUnit_Framework_TestCase {
                $this->assertEquals( $value, $v, "Value still returned after deleted" );
                $this->assertEquals( 1, $wasSet, "Value process cached while deleted" );
 
-               $backToTheFutureCache = new TimeAdjustableWANObjectCache( [
-                       'cache'   => new TimeAdjustableHashBagOStuff(),
-                       'pool'    => 'empty'
-               ] );
-
                $oldValReceived = -1;
                $oldAsOfReceived = -1;
                $checkFunc = function ( $oldVal, &$ttl, array $setOpts, $oldAsOf )
@@ -283,29 +283,84 @@ class WANObjectCacheTest extends PHPUnit_Framework_TestCase {
                        return 'xxx' . $wasSet;
                };
 
+               $now = microtime( true ); // reference time
+
                $wasSet = 0;
                $key = wfRandomString();
-               $v = $backToTheFutureCache->getWithSetCallback(
+               $v = $cache->getWithSetCallback(
                        $key, 30, $checkFunc, [ 'staleTTL' => 50 ] + $extOpts );
                $this->assertEquals( 'xxx1', $v, "Value returned" );
                $this->assertEquals( false, $oldValReceived, "Callback got no stale value" );
                $this->assertEquals( null, $oldAsOfReceived, "Callback got no stale value" );
 
-               $backToTheFutureCache->setTime( microtime( true ) + 40 );
-               $v = $backToTheFutureCache->getWithSetCallback(
+               $cache->addTime( 40 );
+               $v = $cache->getWithSetCallback(
                        $key, 30, $checkFunc, [ 'staleTTL' => 50 ] + $extOpts );
                $this->assertEquals( 'xxx2', $v, "Value still returned after expired" );
                $this->assertEquals( 2, $wasSet, "Value recalculated while expired" );
                $this->assertEquals( 'xxx1', $oldValReceived, "Callback got stale value" );
                $this->assertNotEquals( null, $oldAsOfReceived, "Callback got stale value" );
 
-               $backToTheFutureCache->setTime( microtime( true ) + 300 );
-               $v = $backToTheFutureCache->getWithSetCallback(
+               $cache->addTime( 260 );
+               $v = $cache->getWithSetCallback(
                        $key, 30, $checkFunc, [ 'staleTTL' => 50 ] + $extOpts );
                $this->assertEquals( 'xxx3', $v, "Value still returned after expired" );
                $this->assertEquals( 3, $wasSet, "Value recalculated while expired" );
                $this->assertEquals( false, $oldValReceived, "Callback got no stale value" );
                $this->assertEquals( null, $oldAsOfReceived, "Callback got no stale value" );
+
+               $wasSet = 0;
+               $key = wfRandomString();
+               $checkKey = $cache->makeKey( 'template', 'X' );
+               $cache->setTime( $now - $cache::HOLDOFF_TTL - 1 );
+               $cache->touchCheckKey( $checkKey ); // init check key
+               $cache->setTime( $now );
+               $v = $cache->getWithSetCallback(
+                       $key,
+                       $cache::TTL_INDEFINITE,
+                       $checkFunc,
+                       [ 'graceTTL' => $cache::TTL_WEEK, 'checkKeys' => [ $checkKey ] ] + $extOpts
+               );
+               $this->assertEquals( 'xxx1', $v, "Value returned" );
+               $this->assertEquals( 1, $wasSet, "Value computed" );
+               $this->assertEquals( false, $oldValReceived, "Callback got no stale value" );
+               $this->assertEquals( null, $oldAsOfReceived, "Callback got no stale value" );
+
+               $cache->addTime( $cache::TTL_HOUR ); // some time passes
+               $v = $cache->getWithSetCallback(
+                       $key,
+                       $cache::TTL_INDEFINITE,
+                       $checkFunc,
+                       [ 'graceTTL' => $cache::TTL_WEEK, 'checkKeys' => [ $checkKey ] ] + $extOpts
+               );
+               $this->assertEquals( 'xxx1', $v, "Cached value returned" );
+               $this->assertEquals( 1, $wasSet, "Cached value returned" );
+
+               $cache->touchCheckKey( $checkKey ); // make key stale
+               $cache->addTime( 0.01 ); // ~1 week left of grace (barely stale to avoid refreshes)
+
+               $v = $cache->getWithSetCallback(
+                       $key,
+                       $cache::TTL_INDEFINITE,
+                       $checkFunc,
+                       [ 'graceTTL' => $cache::TTL_WEEK, 'checkKeys' => [ $checkKey ] ] + $extOpts
+               );
+               $this->assertEquals( 'xxx1', $v, "Value still returned after expired (in grace)" );
+               $this->assertEquals( 1, $wasSet, "Value still returned after expired (in grace)" );
+
+               // Change of refresh increase to unity as staleness approaches graceTTL
+
+               $cache->addTime( $cache::TTL_WEEK ); // 8 days of being stale
+               $v = $cache->getWithSetCallback(
+                       $key,
+                       $cache::TTL_INDEFINITE,
+                       $checkFunc,
+                       [ 'graceTTL' => $cache::TTL_WEEK, 'checkKeys' => [ $checkKey ] ] + $extOpts
+               );
+               $this->assertEquals( 'xxx2', $v, "Value was recomputed (past grace)" );
+               $this->assertEquals( 2, $wasSet, "Value was recomputed (past grace)" );
+               $this->assertEquals( 'xxx1', $oldValReceived, "Callback got post-grace stale value" );
+               $this->assertNotEquals( null, $oldAsOfReceived, "Callback got post-grace stale value" );
        }
 
        public static function getWithSetCallback_provider() {
@@ -318,15 +373,15 @@ class WANObjectCacheTest extends PHPUnit_Framework_TestCase {
        public function testPreemtiveRefresh() {
                $value = 'KatCafe';
                $wasSet = 0;
-               $func = function ( $old, &$ttl, &$opts, $asOf ) use ( &$wasSet, $value )
+               $func = function ( $old, &$ttl, &$opts, $asOf ) use ( &$wasSet, &$value )
                {
                        ++$wasSet;
                        return $value;
                };
 
                $cache = new NearExpiringWANObjectCache( [
-                       'cache'   => new HashBagOStuff(),
-                       'pool'    => 'empty'
+                       'cache'        => new HashBagOStuff(),
+                       'pool'         => 'empty',
                ] );
 
                $wasSet = 0;
@@ -347,12 +402,50 @@ class WANObjectCacheTest extends PHPUnit_Framework_TestCase {
                $v = $cache->getWithSetCallback( $key, 30, $func, $opts );
                $this->assertEquals( 1, $wasSet, "Value cached" );
 
+               $asycList = [];
+               $asyncHandler = function ( $callback ) use ( &$asycList ) {
+                       $asycList[] = $callback;
+               };
+               $cache = new NearExpiringWANObjectCache( [
+                       'cache'        => new TimeAdjustableHashBagOStuff(),
+                       'pool'         => 'empty',
+                       'asyncHandler' => $asyncHandler
+               ] );
+
+               $now = microtime( true ); // reference time
+               $cache->setTime( $now );
+
+               $wasSet = 0;
+               $key = wfRandomString();
+               $checkKey = wfRandomString();
+               $opts = [ 'lowTTL' => 100 ];
+               $v = $cache->getWithSetCallback( $key, 300, $func, $opts );
+               $this->assertEquals( $value, $v, "Value returned" );
+               $this->assertEquals( 1, $wasSet, "Value calculated" );
+               $v = $cache->getWithSetCallback( $key, 300, $func, $opts );
+               $this->assertEquals( 1, $wasSet, "Cached value used" );
+               $this->assertEquals( $v, $value, "Value cached" );
+
+               $cache->setTime( $now + 250 );
+               $v = $cache->getWithSetCallback( $key, 300, $func, $opts );
+               $this->assertEquals( $value, $v, "Value returned" );
+               $this->assertEquals( 1, $wasSet, "Stale value used" );
+               $this->assertEquals( 1, count( $asycList ), "Refresh deferred." );
+               $value = 'NewCatsInTown'; // change callback return value
+               $asycList[0](); // run the refresh callback
+               $asycList = [];
+               $this->assertEquals( 2, $wasSet, "Value calculated at later time" );
+               $this->assertEquals( 0, count( $asycList ), "No deferred refreshes added." );
+               $v = $cache->getWithSetCallback( $key, 300, $func, $opts );
+               $this->assertEquals( $value, $v, "New value stored" );
+
                $cache = new PopularityRefreshingWANObjectCache( [
-                       'cache'   => new HashBagOStuff(),
+                       'cache'   => new TimeAdjustableHashBagOStuff(),
                        'pool'    => 'empty'
                ] );
 
-               $now = microtime( true ); // reference time
+               $cache->setTime( $now );
+
                $wasSet = 0;
                $key = wfRandomString();
                $opts = [ 'hotTTR' => 900 ];
@@ -372,6 +465,7 @@ class WANObjectCacheTest extends PHPUnit_Framework_TestCase {
                $this->assertEquals( 1, $wasSet, "Value calculated" );
                $cache->setTime( $now + 30 );
                $v = $cache->getWithSetCallback( $key, 60, $func, $opts );
+               $this->assertEquals( $value, $v, "Value returned" );
                $this->assertEquals( 2, $wasSet, "Value re-calculated" );
        }
 
@@ -443,8 +537,11 @@ class WANObjectCacheTest extends PHPUnit_Framework_TestCase {
                $this->assertEquals( 1, $wasSet, "Value not regenerated" );
                $this->assertEquals( 0, $cache->getWarmupKeyMisses(), "Keys warmed in process cache" );
 
-               $priorTime = microtime( true );
-               usleep( 1 );
+               $priorTime = microtime( true ); // reference time
+               $cache->setTime( $priorTime );
+
+               $cache->addTime( 1 );
+
                $wasSet = 0;
                $keyedIds = new ArrayIterator( [ $keyB => 'efef' ] );
                $v = $cache->getMultiWithSetCallback(
@@ -459,7 +556,7 @@ class WANObjectCacheTest extends PHPUnit_Framework_TestCase {
                $t2 = $cache->getCheckKeyTime( $cKey2 );
                $this->assertGreaterThanOrEqual( $priorTime, $t2, 'Check keys generated on miss' );
 
-               $priorTime = microtime( true );
+               $priorTime = $cache->addTime( 0.01 );
                $value = "@43636$";
                $wasSet = 0;
                $keyedIds = new ArrayIterator( [ $keyC => 43636 ] );
@@ -609,8 +706,11 @@ class WANObjectCacheTest extends PHPUnit_Framework_TestCase {
                $this->assertEquals( 1, $wasSet, "Value not regenerated" );
                $this->assertEquals( 0, $cache->getWarmupKeyMisses(), "Keys warmed in process cache" );
 
-               $priorTime = microtime( true );
-               usleep( 1 );
+               $priorTime = microtime( true ); // reference time
+               $cache->setTime( $priorTime );
+
+               $cache->addTime( 1 );
+
                $wasSet = 0;
                $keyedIds = new ArrayIterator( [ $keyB => 'efef' ] );
                $v = $cache->getMultiWithUnionSetCallback(
@@ -623,7 +723,7 @@ class WANObjectCacheTest extends PHPUnit_Framework_TestCase {
                $t2 = $cache->getCheckKeyTime( $cKey2 );
                $this->assertGreaterThanOrEqual( $priorTime, $t2, 'Check keys generated on miss' );
 
-               $priorTime = microtime( true );
+               $priorTime = $cache->addTime( 0.01 );
                $value = "@43636$";
                $wasSet = 0;
                $keyedIds = new ArrayIterator( [ $keyC => 43636 ] );
@@ -711,8 +811,6 @@ class WANObjectCacheTest extends PHPUnit_Framework_TestCase {
                $calls = 0;
                $func = function () use ( &$calls, $value, $cache, $key ) {
                        ++$calls;
-                       // Immediately kill any mutex rather than waiting a second
-                       $cache->delete( $cache::MUTEX_KEY_PREFIX . $key );
                        return $value;
                };
 
@@ -720,7 +818,7 @@ class WANObjectCacheTest extends PHPUnit_Framework_TestCase {
                $this->assertEquals( $value, $ret );
                $this->assertEquals( 1, $calls, 'Value was populated' );
 
-               // Acquire a lock to verify that getWithSetCallback uses lockTSE properly
+               // Acquire the mutex to verify that getWithSetCallback uses lockTSE properly
                $this->internalCache->add( $cache::MUTEX_KEY_PREFIX . $key, 1, 0 );
 
                $checkKeys = [ wfRandomString() ]; // new check keys => force misses
@@ -737,8 +835,8 @@ class WANObjectCacheTest extends PHPUnit_Framework_TestCase {
 
                $ret = $cache->getWithSetCallback( $key, 30, $func,
                        [ 'lockTSE' => 5, 'checkKeys' => $checkKeys ] );
-               $this->assertEquals( $value, $ret, 'Callback was not used; used interim' );
-               $this->assertEquals( 2, $calls, 'Callback was not used; used interim' );
+               $this->assertEquals( $value, $ret, 'Callback was not used; used interim (mutex failed)' );
+               $this->assertEquals( 2, $calls, 'Callback was not used; used interim (mutex failed)' );
        }
 
        /**
@@ -860,8 +958,11 @@ class WANObjectCacheTest extends PHPUnit_Framework_TestCase {
                $cKey1 = wfRandomString();
                $cKey2 = wfRandomString();
 
-               $priorTime = microtime( true );
-               usleep( 1 );
+               $priorTime = microtime( true ); // reference time
+               $cache->setTime( $priorTime );
+
+               $cache->addTime( 1 );
+
                $curTTLs = [];
                $this->assertEquals(
                        [ $key1 => $value1, $key2 => $value2 ],
@@ -876,7 +977,8 @@ class WANObjectCacheTest extends PHPUnit_Framework_TestCase {
                $this->assertLessThanOrEqual( 0, $curTTLs[$key1], 'Key 1 has current TTL <= 0' );
                $this->assertLessThanOrEqual( 0, $curTTLs[$key2], 'Key 2 has current TTL <= 0' );
 
-               usleep( 1 );
+               $cache->addTime( 1 );
+
                $curTTLs = [];
                $this->assertEquals(
                        [ $key1 => $value1, $key2 => $value2 ],
@@ -902,12 +1004,15 @@ class WANObjectCacheTest extends PHPUnit_Framework_TestCase {
                $value1 = wfRandomString();
                $value2 = wfRandomString();
 
+               $cache->setTime( microtime( true ) );
+
                // Fake initial check key to be set in the past. Otherwise we'd have to sleep for
                // several seconds during the test to assert the behaviour.
                foreach ( [ $checkAll, $check1, $check2 ] as $checkKey ) {
                        $cache->touchCheckKey( $checkKey, WANObjectCache::HOLDOFF_NONE );
                }
-               usleep( 100 );
+
+               $cache->addTime( 0.100 );
 
                $cache->set( 'key1', $value1, 10 );
                $cache->set( 'key2', $value2, 10 );
@@ -929,6 +1034,7 @@ class WANObjectCacheTest extends PHPUnit_Framework_TestCase {
                $this->assertGreaterThanOrEqual( 9.5, $curTTLs['key2'], 'Initial ttls' );
                $this->assertLessThanOrEqual( 10.5, $curTTLs['key2'], 'Initial ttls' );
 
+               $cache->addTime( 0.100 );
                $cache->touchCheckKey( $check1 );
 
                $curTTLs = [];
@@ -1049,53 +1155,69 @@ class WANObjectCacheTest extends PHPUnit_Framework_TestCase {
                $cache = $this->cache;
 
                $key = wfRandomString();
-               $value = wfRandomString();
+               $valueV1 = wfRandomString();
+               $valueV2 = [ wfRandomString() ];
 
                $wasSet = 0;
-               $func = function ( $old, &$ttl ) use ( &$wasSet, $value ) {
+               $funcV1 = function () use ( &$wasSet, $valueV1 ) {
                        ++$wasSet;
-                       return $value;
+
+                       return $valueV1;
+               };
+
+               $priorValue = false;
+               $priorAsOf = null;
+               $funcV2 = function ( $oldValue, &$ttl, $setOpts, $oldAsOf )
+               use ( &$wasSet, $valueV2, &$priorValue, &$priorAsOf ) {
+                       $priorValue = $oldValue;
+                       $priorAsOf = $oldAsOf;
+                       ++$wasSet;
+
+                       return $valueV2; // new array format
                };
 
                // Set the main key (version N if versioned)
                $wasSet = 0;
-               $v = $cache->getWithSetCallback( $key, 30, $func, $extOpts );
-               $this->assertEquals( $value, $v, "Value returned" );
+               $v = $cache->getWithSetCallback( $key, 30, $funcV1, $extOpts );
+               $this->assertEquals( $valueV1, $v, "Value returned" );
                $this->assertEquals( 1, $wasSet, "Value regenerated" );
-               $cache->getWithSetCallback( $key, 30, $func, $extOpts );
+               $cache->getWithSetCallback( $key, 30, $funcV1, $extOpts );
                $this->assertEquals( 1, $wasSet, "Value not regenerated" );
-               // Set the key for version N+1 (if versioned)
+               $this->assertEquals( $valueV1, $v, "Value not regenerated" );
+
                if ( $versioned ) {
+                       // Set the key for version N+1 format
                        $verOpts = [ 'version' => $extOpts['version'] + 1 ];
-
-                       $wasSet = 0;
-                       $v = $cache->getWithSetCallback( $key, 30, $func, $verOpts + $extOpts );
-                       $this->assertEquals( $value, $v, "Value returned" );
-                       $this->assertEquals( 1, $wasSet, "Value regenerated" );
-
-                       $wasSet = 0;
-                       $v = $cache->getWithSetCallback( $key, 30, $func, $verOpts + $extOpts );
-                       $this->assertEquals( $value, $v, "Value returned" );
-                       $this->assertEquals( 0, $wasSet, "Value not regenerated" );
+               } else {
+                       // Start versioning now with the unversioned key still there
+                       $verOpts = [ 'version' => 1 ];
                }
 
+               // Value goes to secondary key since V1 already used $key
                $wasSet = 0;
-               $cache->getWithSetCallback( $key, 30, $func, $extOpts );
-               $this->assertEquals( 0, $wasSet, "Value not regenerated" );
+               $v = $cache->getWithSetCallback( $key, 30, $funcV2, $verOpts + $extOpts );
+               $this->assertEquals( $valueV2, $v, "Value returned" );
+               $this->assertEquals( 1, $wasSet, "Value regenerated" );
+               $this->assertEquals( false, $priorValue, "Old value not given due to old format" );
+               $this->assertEquals( null, $priorAsOf, "Old value not given due to old format" );
 
                $wasSet = 0;
-               $cache->delete( $key );
-               $v = $cache->getWithSetCallback( $key, 30, $func, $extOpts );
-               $this->assertEquals( $value, $v, "Value returned" );
+               $v = $cache->getWithSetCallback( $key, 30, $funcV2, $verOpts + $extOpts );
+               $this->assertEquals( $valueV2, $v, "Value not regenerated (secondary key)" );
+               $this->assertEquals( 0, $wasSet, "Value not regenerated (secondary key)" );
+
+               // Clear out the older or unversioned key
+               $cache->delete( $key, 0 );
+
+               // Set the key for next/first versioned format
+               $wasSet = 0;
+               $v = $cache->getWithSetCallback( $key, 30, $funcV2, $verOpts + $extOpts );
+               $this->assertEquals( $valueV2, $v, "Value returned" );
                $this->assertEquals( 1, $wasSet, "Value regenerated" );
 
-               if ( $versioned ) {
-                       $wasSet = 0;
-                       $verOpts = [ 'version' => $extOpts['version'] + 1 ];
-                       $v = $cache->getWithSetCallback( $key, 30, $func, $verOpts + $extOpts );
-                       $this->assertEquals( $value, $v, "Value returned" );
-                       $this->assertEquals( 1, $wasSet, "Value regenerated" );
-               }
+               $v = $cache->getWithSetCallback( $key, 30, $funcV2, $verOpts + $extOpts );
+               $this->assertEquals( $valueV2, $v, "Value not regenerated (main key)" );
+               $this->assertEquals( 1, $wasSet, "Value not regenerated (main key)" );
        }
 
        public static function getWithSetCallback_versions_provider() {
@@ -1105,44 +1227,100 @@ class WANObjectCacheTest extends PHPUnit_Framework_TestCase {
                ];
        }
 
+       /**
+        * @covers WANObjectCache::useInterimHoldOffCaching
+        * @covers WANObjectCache::getInterimValue
+        */
+       public function testInterimHoldOffCaching() {
+               $cache = $this->cache;
+
+               $value = 'CRL-40-940';
+               $wasCalled = 0;
+               $func = function () use ( &$wasCalled, $value ) {
+                       $wasCalled++;
+
+                       return $value;
+               };
+
+               $cache->useInterimHoldOffCaching( true );
+
+               $key = wfRandomString( 32 );
+               $v = $cache->getWithSetCallback( $key, 60, $func );
+               $v = $cache->getWithSetCallback( $key, 60, $func );
+               $this->assertEquals( 1, $wasCalled, 'Value cached' );
+               $cache->delete( $key );
+               $v = $cache->getWithSetCallback( $key, 60, $func );
+               $this->assertEquals( 2, $wasCalled, 'Value regenerated (got mutex)' ); // sets interim
+               $v = $cache->getWithSetCallback( $key, 60, $func );
+               $this->assertEquals( 3, $wasCalled, 'Value regenerated (got mutex)' ); // sets interim
+               // Lock up the mutex so interim cache is used
+               $this->internalCache->add( $cache::MUTEX_KEY_PREFIX . $key, 1, 0 );
+               $v = $cache->getWithSetCallback( $key, 60, $func );
+               $this->assertEquals( 3, $wasCalled, 'Value interim cached (failed mutex)' );
+               $this->internalCache->delete( $cache::MUTEX_KEY_PREFIX . $key );
+
+               $cache->useInterimHoldOffCaching( false );
+
+               $wasCalled = 0;
+               $key = wfRandomString( 32 );
+               $v = $cache->getWithSetCallback( $key, 60, $func );
+               $v = $cache->getWithSetCallback( $key, 60, $func );
+               $this->assertEquals( 1, $wasCalled, 'Value cached' );
+               $cache->delete( $key );
+               $v = $cache->getWithSetCallback( $key, 60, $func );
+               $this->assertEquals( 2, $wasCalled, 'Value regenerated (got mutex)' );
+               $v = $cache->getWithSetCallback( $key, 60, $func );
+               $this->assertEquals( 3, $wasCalled, 'Value still regenerated (got mutex)' );
+               $v = $cache->getWithSetCallback( $key, 60, $func );
+               $this->assertEquals( 4, $wasCalled, 'Value still regenerated (got mutex)' );
+               // Lock up the mutex so interim cache is used
+               $this->internalCache->add( $cache::MUTEX_KEY_PREFIX . $key, 1, 0 );
+               $v = $cache->getWithSetCallback( $key, 60, $func );
+               $this->assertEquals( 5, $wasCalled, 'Value still regenerated (failed mutex)' );
+       }
+
        /**
         * @covers WANObjectCache::touchCheckKey
         * @covers WANObjectCache::resetCheckKey
         * @covers WANObjectCache::getCheckKeyTime
+        * @covers WANObjectCache::getMultiCheckKeyTime
         * @covers WANObjectCache::makePurgeValue
         * @covers WANObjectCache::parsePurgeValue
         */
        public function testTouchKeys() {
+               $cache = $this->cache;
                $key = wfRandomString();
 
-               $priorTime = microtime( true );
-               usleep( 100 );
-               $t0 = $this->cache->getCheckKeyTime( $key );
+               $priorTime = microtime( true ); // reference time
+               $cache->setTime( $priorTime );
+
+               $newTime = $cache->addTime( 0.100 );
+               $t0 = $cache->getCheckKeyTime( $key );
                $this->assertGreaterThanOrEqual( $priorTime, $t0, 'Check key auto-created' );
 
-               $priorTime = microtime( true );
-               usleep( 100 );
-               $this->cache->touchCheckKey( $key );
-               $t1 = $this->cache->getCheckKeyTime( $key );
+               $priorTime = $newTime;
+               $newTime = $cache->addTime( 0.100 );
+               $cache->touchCheckKey( $key );
+               $t1 = $cache->getCheckKeyTime( $key );
                $this->assertGreaterThanOrEqual( $priorTime, $t1, 'Check key created' );
 
-               $t2 = $this->cache->getCheckKeyTime( $key );
+               $t2 = $cache->getCheckKeyTime( $key );
                $this->assertEquals( $t1, $t2, 'Check key time did not change' );
 
-               usleep( 100 );
-               $this->cache->touchCheckKey( $key );
-               $t3 = $this->cache->getCheckKeyTime( $key );
+               $cache->addTime( 0.100 );
+               $cache->touchCheckKey( $key );
+               $t3 = $cache->getCheckKeyTime( $key );
                $this->assertGreaterThan( $t2, $t3, 'Check key time increased' );
 
-               $t4 = $this->cache->getCheckKeyTime( $key );
+               $t4 = $cache->getCheckKeyTime( $key );
                $this->assertEquals( $t3, $t4, 'Check key time did not change' );
 
-               usleep( 100 );
-               $this->cache->resetCheckKey( $key );
-               $t5 = $this->cache->getCheckKeyTime( $key );
+               $cache->addTime( 0.100 );
+               $cache->resetCheckKey( $key );
+               $t5 = $cache->getCheckKeyTime( $key );
                $this->assertGreaterThan( $t4, $t5, 'Check key time increased' );
 
-               $t6 = $this->cache->getCheckKeyTime( $key );
+               $t6 = $cache->getCheckKeyTime( $key );
                $this->assertEquals( $t5, $t6, 'Check key time did not change' );
        }
 
@@ -1469,6 +1647,15 @@ class TimeAdjustableWANObjectCache extends WANObjectCache {
                }
        }
 
+       public function addTime( $time ) {
+               $this->timeOverride += $time;
+               if ( $this->cache instanceof TimeAdjustableHashBagOStuff ) {
+                       $this->cache->setTime( $this->timeOverride );
+               }
+
+               return $this->timeOverride;
+       }
+
        protected function getCurrentTime() {
                return $this->timeOverride ?: parent::getCurrentTime();
        }
@@ -1478,7 +1665,7 @@ class NearExpiringWANObjectCache extends TimeAdjustableWANObjectCache {
        const CLOCK_SKEW = 1;
 
        protected function worthRefreshExpiring( $curTTL, $lowTTL ) {
-               return ( ( $curTTL + self::CLOCK_SKEW ) < $lowTTL );
+               return ( $curTTL > 0 && ( $curTTL + self::CLOCK_SKEW ) < $lowTTL );
        }
 }