BagOStuffTest.php

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<?php
class BagOStuffTest extends MediaWikiTestCase {
        private $cache;

        protected function setUp() {
                parent::setUp();

                // type defined through parameter
                if ( $this->getCliArg( 'use-bagostuff=' ) ) {
                        $name = $this->getCliArg( 'use-bagostuff=' );

                        $this->cache = ObjectCache::newFromId( $name );

                } else {
                        // no type defined - use simple hash
                        $this->cache = new HashBagOStuff;
                }

                $this->cache->delete( wfMemcKey( 'test' ) );
        }

        protected function tearDown() {
        }

        public function testMerge() {
                $key = wfMemcKey( 'test' );

                $usleep = 0;

                $callback = function ( BagOStuff $cache, $key, $existingValue ) use ( &$usleep ) {
                        // let's pretend this is an expensive callback to test concurrent merge attempts
                        usleep( $usleep );

                        if ( $existingValue === false ) {
                                return 'merged';
                        }

                        return $existingValue . 'merged';
                };

                // merge on non-existing value
                $merged = $this->cache->merge( $key, $callback, 0 );
                $this->assertTrue( $merged );
                $this->assertEquals( $this->cache->get( $key ), 'merged' );

                // merge on existing value
                $merged = $this->cache->merge( $key, $callback, 0 );
                $this->assertTrue( $merged );
                $this->assertEquals( $this->cache->get( $key ), 'mergedmerged' );

                /*
                 * Test concurrent merges by forking this process, if:
                 * - not manually called with --use-bagostuff
                 * - pcntl_fork is supported by the system
                 * - cache type will correctly support calls over forks
                 */
                $fork = (bool)$this->getCliArg( 'use-bagostuff=' );
                $fork &= function_exists( 'pcntl_fork' );
                $fork &= !$this->cache instanceof HashBagOStuff;
                $fork &= !$this->cache instanceof EmptyBagOStuff;
                $fork &= !$this->cache instanceof MultiWriteBagOStuff;
                if ( $fork ) {
                        // callback should take awhile now so that we can test concurrent merge attempts
                        $usleep = 5000;

                        $pid = pcntl_fork();
                        if ( $pid == -1 ) {
                                // can't fork, ignore this test...
                        } elseif ( $pid ) {
                                // wait a little, making sure that the child process is calling merge
                                usleep( 3000 );

                                // attempt a merge - this should fail
                                $merged = $this->cache->merge( $key, $callback, 0, 1 );

                                // merge has failed because child process was merging (and we only attempted once)
                                $this->assertFalse( $merged );

                                // make sure the child's merge is completed and verify
                                usleep( 3000 );
                                $this->assertEquals( $this->cache->get( $key ), 'mergedmergedmerged' );
                        } else {
                                $this->cache->merge( $key, $callback, 0, 1 );

                                // Note: I'm not even going to check if the merge worked, I'll
                                // compare values in the parent process to test if this merge worked.
                                // I'm just going to exit this child process, since I don't want the
                                // child to output any test results (would be rather confusing to
                                // have test output twice)
                                exit;
                        }
                }
        }

        public function testAdd() {
                $key = wfMemcKey( 'test' );
                $this->assertTrue( $this->cache->add( $key, 'test' ) );
        }

        public function testGet() {
                $value = array( 'this' => 'is', 'a' => 'test' );

                $key = wfMemcKey( 'test' );
                $this->cache->add( $key, $value );
                $this->assertEquals( $this->cache->get( $key ), $value );
        }

        public function testGetMulti() {
                $value1 = array( 'this' => 'is', 'a' => 'test' );
                $value2 = array( 'this' => 'is', 'another' => 'test' );

                $key1 = wfMemcKey( 'test1' );
                $key2 = wfMemcKey( 'test2' );

                $this->cache->add( $key1, $value1 );
                $this->cache->add( $key2, $value2 );

                $this->assertEquals( $this->cache->getMulti( array( $key1, $key2 ) ), array( $key1 => $value1, $key2 => $value2 ) );

                // cleanup
                $this->cache->delete( $key1 );
                $this->cache->delete( $key2 );
        }
}