tests/phpunit/includes/objectcache/BagOStuffTest.php

   1 <?php
   2 /**
   3  * This class will test BagOStuff.
   4  *
   5  * @author     Matthias Mullie <mmullie@wikimedia.org>
   6  */
   7 class BagOStuffTest extends MediaWikiTestCase {
   8         private $cache;
   9
  10         protected function setUp() {
  11                 parent::setUp();
  12
  13                 // type defined through parameter
  14                 if ( $this->getCliArg( 'use-bagostuff=' ) ) {
  15                         $name = $this->getCliArg( 'use-bagostuff=' );
  16
  17                         $this->cache = ObjectCache::newFromId( $name );
  18
  19                 // no type defined - use simple hash
  20                 } else {
  21                         $this->cache = new HashBagOStuff;
  22                 }
  23
  24                 $this->cache->delete( wfMemcKey( 'test' ) );
  25         }
  26
  27         protected function tearDown() {
  28         }
  29
  30         public function testMerge() {
  31                 $key = wfMemcKey( 'test' );
  32
  33                 $usleep = 0;
  34
  35                 /**
  36                  * Callback method: append "merged" to whatever is in cache.
  37                  *
  38                  * @param BagOStuff $cache
  39                  * @param string $key
  40                  * @param int $existingValue
  41                  * @use int $usleep
  42                  * @return int
  43                  */
  44                 $callback = function( BagOStuff $cache, $key, $existingValue ) use ( &$usleep ) {
  45                         // let's pretend this is an expensive callback to test concurrent merge attempts
  46                         usleep( $usleep );
  47
  48                         if ( $existingValue === false ) {
  49                                 return 'merged';
  50                         }
  51
  52                         return $existingValue . 'merged';
  53                 };
  54
  55                 // merge on non-existing value
  56                 $merged = $this->cache->merge( $key, $callback, 0 );
  57                 $this->assertTrue( $merged );
  58                 $this->assertEquals( $this->cache->get( $key ), 'merged' );
  59
  60                 // merge on existing value
  61                 $merged = $this->cache->merge( $key, $callback, 0 );
  62                 $this->assertTrue( $merged );
  63                 $this->assertEquals( $this->cache->get( $key ), 'mergedmerged' );
  64
  65                 /*
  66                  * Test concurrent merges by forking this process, if:
  67                  * - not manually called with --use-bagostuff
  68                  * - pcntl_fork is supported by the system
  69                  * - cache type will correctly support calls over forks
  70                  */
  71                 $fork = (bool) $this->getCliArg( 'use-bagostuff=' );
  72                 $fork &= function_exists( 'pcntl_fork' );
  73                 $fork &= !$this->cache instanceof HashBagOStuff;
  74                 $fork &= !$this->cache instanceof EmptyBagOStuff;
  75                 $fork &= !$this->cache instanceof MultiWriteBagOStuff;
  76                 if ( $fork ) {
  77                         // callback should take awhile now so that we can test concurrent merge attempts
  78                         $usleep = 5000;
  79
  80                         $pid = pcntl_fork();
  81                         if ( $pid == -1 ) {
  82                                 // can't fork, ignore this test...
  83                         } elseif ( $pid ) {
  84                                 // wait a little, making sure that the child process is calling merge
  85                                 usleep( 3000 );
  86
  87                                 // attempt a merge - this should fail
  88                                 $merged = $this->cache->merge( $key, $callback, 0, 1 );
  89
  90                                 // merge has failed because child process was merging (and we only attempted once)
  91                                 $this->assertFalse( $merged );
  92
  93                                 // make sure the child's merge is completed and verify
  94                                 usleep( 3000 );
  95                                 $this->assertEquals( $this->cache->get( $key ), 'mergedmergedmerged' );
  96                         } else {
  97                                 $this->cache->merge( $key, $callback, 0, 1 );
  98
  99                                 // Note: I'm not even going to check if the merge worked, I'll
 100                                 // compare values in the parent process to test if this merge worked.
 101                                 // I'm just going to exit this child process, since I don't want the
 102                                 // child to output any test results (would be rather confusing to
 103                                 // have test output twice)
 104                                 exit;
 105                         }
 106                 }
 107         }
 108 }