MediaWikiTestCase.php

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<?php
 
use MediaWiki\Logger\LegacySpi;
use MediaWiki\Logger\LoggerFactory;
use MediaWiki\Logger\MonologSpi;
use MediaWiki\Logger\LogCapturingSpi;
use MediaWiki\MediaWikiServices;
use Psr\Log\LoggerInterface;
use Wikimedia\Rdbms\IDatabase;
use Wikimedia\Rdbms\IMaintainableDatabase;
use Wikimedia\Rdbms\Database;
use Wikimedia\TestingAccessWrapper;
 
abstract class MediaWikiTestCase extends PHPUnit\Framework\TestCase {
 
    use MediaWikiCoversValidator;
    use PHPUnit4And6Compat;
 
    private static $originalServices;
 
    private $localServices;
 
    private $called = [];
 
    public static $users;
 
    protected $db;
 
    protected $tablesUsed = []; // tables with data
 
    private static $useTemporaryTables = true;
    private static $reuseDB = false;
    private static $dbSetup = false;
    private static $oldTablePrefix = '';
 
    private $phpErrorLevel;
 
    private $tmpFiles = [];
 
    private $mwGlobals = [];
 
    private $mwGlobalsToUnset = [];
 
    private $iniSettings = [];
 
    private $loggers = [];
 
    private $cliArgs = [];
 
    private $overriddenServices = [];
 
    const DB_PREFIX = 'unittest_';
    const ORA_DB_PREFIX = 'ut_';
 
    protected $supportedDBs = [
        'mysql',
        'sqlite',
        'postgres',
        'oracle'
    ];
 
    public function __construct( $name = null, array $data = [], $dataName = '' ) {
        parent::__construct( $name, $data, $dataName );
 
        $this->backupGlobals = false;
        $this->backupStaticAttributes = false;
    }
 
    public function __destruct() {
        // Complain if self::setUp() was called, but not self::tearDown()
        // $this->called['setUp'] will be checked by self::testMediaWikiTestCaseParentSetupCalled()
        if ( isset( $this->called['setUp'] ) && !isset( $this->called['tearDown'] ) ) {
            throw new MWException( static::class . "::tearDown() must call parent::tearDown()" );
        }
    }
 
    public static function setUpBeforeClass() {
        parent::setUpBeforeClass();
 
        // Get the original service locator
        if ( !self::$originalServices ) {
            self::$originalServices = MediaWikiServices::getInstance();
        }
    }
 
    public static function getTestUser( $groups = [] ) {
        return TestUserRegistry::getImmutableTestUser( $groups );
    }
 
    public static function getMutableTestUser( $groups = [] ) {
        return TestUserRegistry::getMutableTestUser( __CLASS__, $groups );
    }
 
    public static function getTestSysop() {
        return self::getTestUser( [ 'sysop', 'bureaucrat' ] );
    }
 
    protected function getExistingTestPage( $title = null ) {
        if ( !$this->needsDB() ) {
            throw new MWException( 'When testing which pages, the test cases\'s needsDB()' .
                ' method should return true. Use @group Database or $this->tablesUsed.' );
        }
 
        $title = ( $title === null ) ? 'UTPage' : $title;
        $title = is_string( $title ) ? Title::newFromText( $title ) : $title;
        $page = WikiPage::factory( $title );
 
        if ( !$page->exists() ) {
            $user = self::getTestSysop()->getUser();
            $page->doEditContent(
                new WikitextContent( 'UTContent' ),
                'UTPageSummary',
                EDIT_NEW | EDIT_SUPPRESS_RC,
                false,
                $user
            );
        }
 
        return $page;
    }
 
    protected function getNonexistingTestPage( $title = null ) {
        if ( !$this->needsDB() ) {
            throw new MWException( 'When testing which pages, the test cases\'s needsDB()' .
                ' method should return true. Use @group Database or $this->tablesUsed.' );
        }
 
        $title = ( $title === null ) ? 'UTPage-' . rand( 0, 100000 ) : $title;
        $title = is_string( $title ) ? Title::newFromText( $title ) : $title;
        $page = WikiPage::factory( $title );
 
        if ( $page->exists() ) {
            $page->doDeleteArticle( 'Testing' );
        }
 
        return $page;
    }
 
    public static function prepareServices( Config $bootstrapConfig ) {
    }
 
    private static function makeTestConfig(
        Config $baseConfig = null,
        Config $customOverrides = null
    ) {
        $defaultOverrides = new HashConfig();
 
        if ( !$baseConfig ) {
            $baseConfig = self::$originalServices->getBootstrapConfig();
        }
 
        /* Some functions require some kind of caching, and will end up using the db,
         * which we can't allow, as that would open a new connection for mysql.
         * Replace with a HashBag. They would not be going to persist anyway.
         */
        $hashCache = [ 'class' => HashBagOStuff::class, 'reportDupes' => false ];
        $objectCaches = [
                CACHE_DB => $hashCache,
                CACHE_ACCEL => $hashCache,
                CACHE_MEMCACHED => $hashCache,
                'apc' => $hashCache,
                'apcu' => $hashCache,
                'wincache' => $hashCache,
            ] + $baseConfig->get( 'ObjectCaches' );
 
        $defaultOverrides->set( 'ObjectCaches', $objectCaches );
        $defaultOverrides->set( 'MainCacheType', CACHE_NONE );
        $defaultOverrides->set( 'JobTypeConf', [ 'default' => [ 'class' => JobQueueMemory::class ] ] );
 
        // Use a fast hash algorithm to hash passwords.
        $defaultOverrides->set( 'PasswordDefault', 'A' );
 
        $testConfig = $customOverrides
            ? new MultiConfig( [ $customOverrides, $defaultOverrides, $baseConfig ] )
            : new MultiConfig( [ $defaultOverrides, $baseConfig ] );
 
        return $testConfig;
    }
 
    private static function makeTestConfigFactoryInstantiator(
        ConfigFactory $oldFactory,
        array $configurations
    ) {
        return function ( MediaWikiServices $services ) use ( $oldFactory, $configurations ) {
            $factory = new ConfigFactory();
 
            // clone configurations from $oldFactory that are not overwritten by $configurations
            $namesToClone = array_diff(
                $oldFactory->getConfigNames(),
                array_keys( $configurations )
            );
 
            foreach ( $namesToClone as $name ) {
                $factory->register( $name, $oldFactory->makeConfig( $name ) );
            }
 
            foreach ( $configurations as $name => $config ) {
                $factory->register( $name, $config );
            }
 
            return $factory;
        };
    }
 
    public static function resetNonServiceCaches() {
        global $wgRequest, $wgJobClasses;
 
        User::resetGetDefaultOptionsForTestsOnly();
        foreach ( $wgJobClasses as $type => $class ) {
            JobQueueGroup::singleton()->get( $type )->delete();
        }
        JobQueueGroup::destroySingletons();
 
        ObjectCache::clear();
        FileBackendGroup::destroySingleton();
        DeferredUpdates::clearPendingUpdates();
 
        // TODO: move global state into MediaWikiServices
        RequestContext::resetMain();
        if ( session_id() !== '' ) {
            session_write_close();
            session_id( '' );
        }
 
        $wgRequest = new FauxRequest();
        MediaWiki\Session\SessionManager::resetCache();
    }
 
    public function run( PHPUnit_Framework_TestResult $result = null ) {
        if ( $result instanceof MediaWikiTestResult ) {
            $this->cliArgs = $result->getMediaWikiCliArgs();
        }
        $this->overrideMwServices();
 
        if ( $this->needsDB() && !$this->isTestInDatabaseGroup() ) {
            throw new Exception(
                get_class( $this ) . ' apparently needsDB but is not in the Database group'
            );
        }
 
        $needsResetDB = false;
        if ( !self::$dbSetup || $this->needsDB() ) {
            // set up a DB connection for this test to use
 
            self::$useTemporaryTables = !$this->getCliArg( 'use-normal-tables' );
            self::$reuseDB = $this->getCliArg( 'reuse-db' );
 
            $lb = MediaWikiServices::getInstance()->getDBLoadBalancer();
            $this->db = $lb->getConnection( DB_MASTER );
 
            $this->checkDbIsSupported();
 
            if ( !self::$dbSetup ) {
                $this->setupAllTestDBs();
                $this->addCoreDBData();
            }
 
            // TODO: the DB setup should be done in setUpBeforeClass(), so the test DB
            // is available in subclass's setUpBeforeClass() and setUp() methods.
            // This would also remove the need for the HACK that is oncePerClass().
            if ( $this->oncePerClass() ) {
                $this->setUpSchema( $this->db );
                $this->resetDB( $this->db, $this->tablesUsed );
                $this->addDBDataOnce();
            }
 
            $this->addDBData();
            $needsResetDB = true;
        }
 
        parent::run( $result );
 
        // We don't mind if we override already-overridden services during cleanup
        $this->overriddenServices = [];
 
        if ( $needsResetDB ) {
            $this->resetDB( $this->db, $this->tablesUsed );
        }
 
        self::restoreMwServices();
        $this->localServices = null;
    }
 
    private function oncePerClass() {
        // Remember current test class in the database connection,
        // so we know when we need to run addData.
 
        $class = static::class;
 
        $first = !isset( $this->db->_hasDataForTestClass )
            || $this->db->_hasDataForTestClass !== $class;
 
        $this->db->_hasDataForTestClass = $class;
        return $first;
    }
 
    public function usesTemporaryTables() {
        return self::$useTemporaryTables;
    }
 
    protected function getNewTempFile() {
        $fileName = tempnam( wfTempDir(), 'MW_PHPUnit_' . static::class . '_' );
        $this->tmpFiles[] = $fileName;
 
        return $fileName;
    }
 
    protected function getNewTempDirectory() {
        // Starting of with a temporary /file/.
        $fileName = $this->getNewTempFile();
 
        // Converting the temporary /file/ to a /directory/
        // The following is not atomic, but at least we now have a single place,
        // where temporary directory creation is bundled and can be improved
        unlink( $fileName );
        $this->assertTrue( wfMkdirParents( $fileName ) );
 
        return $fileName;
    }
 
    protected function setUp() {
        parent::setUp();
        $this->called['setUp'] = true;
 
        $this->phpErrorLevel = intval( ini_get( 'error_reporting' ) );
 
        $this->overriddenServices = [];
 
        // Cleaning up temporary files
        foreach ( $this->tmpFiles as $fileName ) {
            if ( is_file( $fileName ) || ( is_link( $fileName ) ) ) {
                unlink( $fileName );
            } elseif ( is_dir( $fileName ) ) {
                wfRecursiveRemoveDir( $fileName );
            }
        }
 
        if ( $this->needsDB() && $this->db ) {
            // Clean up open transactions
            while ( $this->db->trxLevel() > 0 ) {
                $this->db->rollback( __METHOD__, 'flush' );
            }
            // Check for unsafe queries
            if ( $this->db->getType() === 'mysql' ) {
                $this->db->query( "SET sql_mode = 'STRICT_ALL_TABLES'", __METHOD__ );
            }
        }
 
        // Reset all caches between tests.
        self::resetNonServiceCaches();
 
        // XXX: reset maintenance triggers
        // Hook into period lag checks which often happen in long-running scripts
        $lbFactory = $this->localServices->getDBLoadBalancerFactory();
        Maintenance::setLBFactoryTriggers( $lbFactory, $this->localServices->getMainConfig() );
 
        ob_start( 'MediaWikiTestCase::wfResetOutputBuffersBarrier' );
    }
 
    protected function addTmpFiles( $files ) {
        $this->tmpFiles = array_merge( $this->tmpFiles, (array)$files );
    }
 
    protected function tearDown() {
        global $wgRequest, $wgSQLMode;
 
        $status = ob_get_status();
        if ( isset( $status['name'] ) &&
            $status['name'] === 'MediaWikiTestCase::wfResetOutputBuffersBarrier'
        ) {
            ob_end_flush();
        }
 
        $this->called['tearDown'] = true;
        // Cleaning up temporary files
        foreach ( $this->tmpFiles as $fileName ) {
            if ( is_file( $fileName ) || ( is_link( $fileName ) ) ) {
                unlink( $fileName );
            } elseif ( is_dir( $fileName ) ) {
                wfRecursiveRemoveDir( $fileName );
            }
        }
 
        if ( $this->needsDB() && $this->db ) {
            // Clean up open transactions
            while ( $this->db->trxLevel() > 0 ) {
                $this->db->rollback( __METHOD__, 'flush' );
            }
            if ( $this->db->getType() === 'mysql' ) {
                $this->db->query( "SET sql_mode = " . $this->db->addQuotes( $wgSQLMode ),
                    __METHOD__ );
            }
        }
 
        // Re-enable any disabled deprecation warnings
        MWDebug::clearLog();
        // Restore mw globals
        foreach ( $this->mwGlobals as $key => $value ) {
            $GLOBALS[$key] = $value;
        }
        foreach ( $this->mwGlobalsToUnset as $value ) {
            unset( $GLOBALS[$value] );
        }
        foreach ( $this->iniSettings as $name => $value ) {
            ini_set( $name, $value );
        }
        if (
            array_key_exists( 'wgExtraNamespaces', $this->mwGlobals ) ||
            in_array( 'wgExtraNamespaces', $this->mwGlobalsToUnset )
        ) {
            $this->resetNamespaces();
        }
        $this->mwGlobals = [];
        $this->mwGlobalsToUnset = [];
        $this->restoreLoggers();
 
        // TODO: move global state into MediaWikiServices
        RequestContext::resetMain();
        if ( session_id() !== '' ) {
            session_write_close();
            session_id( '' );
        }
        $wgRequest = new FauxRequest();
        MediaWiki\Session\SessionManager::resetCache();
        MediaWiki\Auth\AuthManager::resetCache();
 
        $phpErrorLevel = intval( ini_get( 'error_reporting' ) );
 
        if ( $phpErrorLevel !== $this->phpErrorLevel ) {
            ini_set( 'error_reporting', $this->phpErrorLevel );
 
            $oldHex = strtoupper( dechex( $this->phpErrorLevel ) );
            $newHex = strtoupper( dechex( $phpErrorLevel ) );
            $message = "PHP error_reporting setting was left dirty: "
                . "was 0x$oldHex before test, 0x$newHex after test!";
 
            $this->fail( $message );
        }
 
        parent::tearDown();
    }
 
    final public function testMediaWikiTestCaseParentSetupCalled() {
        $this->assertArrayHasKey( 'setUp', $this->called,
            static::class . '::setUp() must call parent::setUp()'
        );
    }
 
    protected function setService( $name, $object ) {
        if ( !$this->localServices ) {
            throw new Exception( __METHOD__ . ' must be called after MediaWikiTestCase::run()' );
        }
 
        if ( $this->localServices !== MediaWikiServices::getInstance() ) {
            throw new Exception( __METHOD__ . ' will not work because the global MediaWikiServices '
                . 'instance has been replaced by test code.' );
        }
 
        $this->overriddenServices[] = $name;
 
        $this->localServices->disableService( $name );
        $this->localServices->redefineService(
            $name,
            function () use ( $object ) {
                return $object;
            }
        );
 
        if ( $name === 'ContentLanguage' ) {
            $this->doSetMwGlobals( [ 'wgContLang' => $object ] );
        }
    }
 
    protected function setMwGlobals( $pairs, $value = null ) {
        if ( is_string( $pairs ) ) {
            $pairs = [ $pairs => $value ];
        }
 
        if ( isset( $pairs['wgContLang'] ) ) {
            throw new MWException(
                'No setting $wgContLang, use setContentLang() or setService( \'ContentLanguage\' )'
            );
        }
 
        $this->doSetMwGlobals( $pairs, $value );
    }
 
    private function doSetMwGlobals( $pairs, $value = null ) {
        $this->doStashMwGlobals( array_keys( $pairs ) );
 
        foreach ( $pairs as $key => $value ) {
            $GLOBALS[$key] = $value;
        }
 
        if ( array_key_exists( 'wgExtraNamespaces', $pairs ) ) {
            $this->resetNamespaces();
        }
    }
 
    protected function setIniSetting( $name, $value ) {
        $original = ini_get( $name );
        $this->iniSettings[$name] = $original;
        ini_set( $name, $value );
    }
 
    private function resetNamespaces() {
        if ( !$this->localServices ) {
            throw new Exception( __METHOD__ . ' must be called after MediaWikiTestCase::run()' );
        }
 
        if ( $this->localServices !== MediaWikiServices::getInstance() ) {
            throw new Exception( __METHOD__ . ' will not work because the global MediaWikiServices '
                . 'instance has been replaced by test code.' );
        }
 
        MWNamespace::clearCaches();
        Language::clearCaches();
 
        // We can't have the TitleFormatter holding on to an old Language object either
        // @todo We shouldn't need to reset all the aliases here.
        $this->localServices->resetServiceForTesting( 'TitleFormatter' );
        $this->localServices->resetServiceForTesting( 'TitleParser' );
        $this->localServices->resetServiceForTesting( '_MediaWikiTitleCodec' );
    }
 
    private static function canShallowCopy( $value ) {
        if ( is_scalar( $value ) || $value === null ) {
            return true;
        }
        if ( is_array( $value ) ) {
            foreach ( $value as $subValue ) {
                if ( !is_scalar( $subValue ) && $subValue !== null ) {
                    return false;
                }
            }
            return true;
        }
        return false;
    }
 
    protected function stashMwGlobals( $globalKeys ) {
        wfDeprecated( __METHOD__, '1.32' );
        $this->doStashMwGlobals( $globalKeys );
    }
 
    private function doStashMwGlobals( $globalKeys ) {
        if ( is_string( $globalKeys ) ) {
            $globalKeys = [ $globalKeys ];
        }
 
        foreach ( $globalKeys as $globalKey ) {
            // NOTE: make sure we only save the global once or a second call to
            // setMwGlobals() on the same global would override the original
            // value.
            if (
                !array_key_exists( $globalKey, $this->mwGlobals ) &&
                !array_key_exists( $globalKey, $this->mwGlobalsToUnset )
            ) {
                if ( !array_key_exists( $globalKey, $GLOBALS ) ) {
                    $this->mwGlobalsToUnset[$globalKey] = $globalKey;
                    continue;
                }
                // NOTE: we serialize then unserialize the value in case it is an object
                // this stops any objects being passed by reference. We could use clone
                // and if is_object but this does account for objects within objects!
                if ( self::canShallowCopy( $GLOBALS[$globalKey] ) ) {
                    $this->mwGlobals[$globalKey] = $GLOBALS[$globalKey];
                } elseif (
                    // Many MediaWiki types are safe to clone. These are the
                    // ones that are most commonly stashed.
                    $GLOBALS[$globalKey] instanceof Language ||
                    $GLOBALS[$globalKey] instanceof User ||
                    $GLOBALS[$globalKey] instanceof FauxRequest
                ) {
                    $this->mwGlobals[$globalKey] = clone $GLOBALS[$globalKey];
                } elseif ( $this->containsClosure( $GLOBALS[$globalKey] ) ) {
                    // Serializing Closure only gives a warning on HHVM while
                    // it throws an Exception on Zend.
                    // Workaround for https://github.com/facebook/hhvm/issues/6206
                    $this->mwGlobals[$globalKey] = $GLOBALS[$globalKey];
                } else {
                    try {
                        $this->mwGlobals[$globalKey] = unserialize( serialize( $GLOBALS[$globalKey] ) );
                    } catch ( Exception $e ) {
                        $this->mwGlobals[$globalKey] = $GLOBALS[$globalKey];
                    }
                }
            }
        }
    }
 
    private function containsClosure( $var, $maxDepth = 15 ) {
        if ( $var instanceof Closure ) {
            return true;
        }
        if ( !is_array( $var ) || $maxDepth === 0 ) {
            return false;
        }
 
        foreach ( $var as $value ) {
            if ( $this->containsClosure( $value, $maxDepth - 1 ) ) {
                return true;
            }
        }
        return false;
    }
 
    protected function mergeMwGlobalArrayValue( $name, $values ) {
        if ( !isset( $GLOBALS[$name] ) ) {
            $merged = $values;
        } else {
            if ( !is_array( $GLOBALS[$name] ) ) {
                throw new MWException( "MW global $name is not an array." );
            }
 
            // NOTE: do not use array_merge, it screws up for numeric keys.
            $merged = $GLOBALS[$name];
            foreach ( $values as $k => $v ) {
                $merged[$k] = $v;
            }
        }
 
        $this->setMwGlobals( $name, $merged );
    }
 
    protected function overrideMwServices(
        Config $configOverrides = null, array $services = []
    ) {
        if ( $this->overriddenServices ) {
            throw new MWException(
                'The following services were set and are now being unset by overrideMwServices: ' .
                    implode( ', ', $this->overriddenServices )
            );
        }
        $newInstance = self::installMockMwServices( $configOverrides );
 
        if ( $this->localServices ) {
            $this->localServices->destroy();
        }
 
        $this->localServices = $newInstance;
 
        foreach ( $services as $name => $callback ) {
            $newInstance->redefineService( $name, $callback );
        }
 
        return $newInstance;
    }
 
    public static function installMockMwServices( Config $configOverrides = null ) {
        // Make sure we have the original service locator
        if ( !self::$originalServices ) {
            self::$originalServices = MediaWikiServices::getInstance();
        }
 
        if ( !$configOverrides ) {
            $configOverrides = new HashConfig();
        }
 
        $oldConfigFactory = self::$originalServices->getConfigFactory();
        $oldLoadBalancerFactory = self::$originalServices->getDBLoadBalancerFactory();
 
        $testConfig = self::makeTestConfig( null, $configOverrides );
        $newServices = new MediaWikiServices( $testConfig );
 
        // Load the default wiring from the specified files.
        // NOTE: this logic mirrors the logic in MediaWikiServices::newInstance.
        $wiringFiles = $testConfig->get( 'ServiceWiringFiles' );
        $newServices->loadWiringFiles( $wiringFiles );
 
        // Provide a traditional hook point to allow extensions to configure services.
        Hooks::run( 'MediaWikiServices', [ $newServices ] );
 
        // Use bootstrap config for all configuration.
        // This allows config overrides via global variables to take effect.
        $bootstrapConfig = $newServices->getBootstrapConfig();
        $newServices->resetServiceForTesting( 'ConfigFactory' );
        $newServices->redefineService(
            'ConfigFactory',
            self::makeTestConfigFactoryInstantiator(
                $oldConfigFactory,
                [ 'main' => $bootstrapConfig ]
            )
        );
        $newServices->resetServiceForTesting( 'DBLoadBalancerFactory' );
        $newServices->redefineService(
            'DBLoadBalancerFactory',
            function ( MediaWikiServices $services ) use ( $oldLoadBalancerFactory ) {
                return $oldLoadBalancerFactory;
            }
        );
 
        MediaWikiServices::forceGlobalInstance( $newServices );
        return $newServices;
    }
 
    public static function restoreMwServices() {
        if ( !self::$originalServices ) {
            return false;
        }
 
        $currentServices = MediaWikiServices::getInstance();
 
        if ( self::$originalServices === $currentServices ) {
            return false;
        }
 
        MediaWikiServices::forceGlobalInstance( self::$originalServices );
        $currentServices->destroy();
 
        return true;
    }
 
    public function setUserLang( $lang ) {
        RequestContext::getMain()->setLanguage( $lang );
        $this->setMwGlobals( 'wgLang', RequestContext::getMain()->getLanguage() );
    }
 
    public function setContentLang( $lang ) {
        if ( $lang instanceof Language ) {
            $this->setMwGlobals( 'wgLanguageCode', $lang->getCode() );
            // Set to the exact object requested
            $this->setService( 'ContentLanguage', $lang );
        } else {
            $this->setMwGlobals( 'wgLanguageCode', $lang );
            // Let the service handler make up the object.  Avoid calling setService(), because if
            // we do, overrideMwServices() will complain if it's called later on.
            $services = MediaWikiServices::getInstance();
            $services->resetServiceForTesting( 'ContentLanguage' );
            $this->doSetMwGlobals( [ 'wgContLang' => $services->getContentLanguage() ] );
        }
    }
 
    public function setGroupPermissions( $newPerms, $newKey = null, $newValue = null ) {
        global $wgGroupPermissions;
 
        if ( is_string( $newPerms ) ) {
            $newPerms = [ $newPerms => [ $newKey => $newValue ] ];
        }
 
        $newPermissions = $wgGroupPermissions;
        foreach ( $newPerms as $group => $permissions ) {
            foreach ( $permissions as $key => $value ) {
                $newPermissions[$group][$key] = $value;
            }
        }
 
        $this->setMwGlobals( 'wgGroupPermissions', $newPermissions );
    }
 
    protected function setLogger( $channel, LoggerInterface $logger ) {
        // TODO: Once loggers are managed by MediaWikiServices, use
        //       overrideMwServices() to set loggers.
 
        $provider = LoggerFactory::getProvider();
        $wrappedProvider = TestingAccessWrapper::newFromObject( $provider );
        $singletons = $wrappedProvider->singletons;
        if ( $provider instanceof MonologSpi ) {
            if ( !isset( $this->loggers[$channel] ) ) {
                $this->loggers[$channel] = $singletons['loggers'][$channel] ?? null;
            }
            $singletons['loggers'][$channel] = $logger;
        } elseif ( $provider instanceof LegacySpi || $provider instanceof LogCapturingSpi ) {
            if ( !isset( $this->loggers[$channel] ) ) {
                $this->loggers[$channel] = $singletons[$channel] ?? null;
            }
            $singletons[$channel] = $logger;
        } else {
            throw new LogicException( __METHOD__ . ': setting a logger for ' . get_class( $provider )
                . ' is not implemented' );
        }
        $wrappedProvider->singletons = $singletons;
    }
 
    private function restoreLoggers() {
        $provider = LoggerFactory::getProvider();
        $wrappedProvider = TestingAccessWrapper::newFromObject( $provider );
        $singletons = $wrappedProvider->singletons;
        foreach ( $this->loggers as $channel => $logger ) {
            if ( $provider instanceof MonologSpi ) {
                if ( $logger === null ) {
                    unset( $singletons['loggers'][$channel] );
                } else {
                    $singletons['loggers'][$channel] = $logger;
                }
            } elseif ( $provider instanceof LegacySpi || $provider instanceof LogCapturingSpi ) {
                if ( $logger === null ) {
                    unset( $singletons[$channel] );
                } else {
                    $singletons[$channel] = $logger;
                }
            }
        }
        $wrappedProvider->singletons = $singletons;
        $this->loggers = [];
    }
 
    public function dbPrefix() {
        return self::getTestPrefixFor( $this->db );
    }
 
    public static function getTestPrefixFor( IDatabase $db ) {
        return $db->getType() == 'oracle' ? self::ORA_DB_PREFIX : self::DB_PREFIX;
    }
 
    public function needsDB() {
        // If the test says it uses database tables, it needs the database
        return $this->tablesUsed || $this->isTestInDatabaseGroup();
    }
 
    protected function isTestInDatabaseGroup() {
        // If the test class says it belongs to the Database group, it needs the database.
        // NOTE: This ONLY checks for the group in the class level doc comment.
        $rc = new ReflectionClass( $this );
        return (bool)preg_match( '/@group +Database/im', $rc->getDocComment() );
    }
 
    protected function insertPage(
        $pageName,
        $text = 'Sample page for unit test.',
        $namespace = null,
        User $user = null
    ) {
        if ( !$this->needsDB() ) {
            throw new MWException( 'When testing which pages, the test cases\'s needsDB()' .
                ' method should return true. Use @group Database or $this->tablesUsed.' );
        }
 
        if ( is_string( $pageName ) ) {
            $title = Title::newFromText( $pageName, $namespace );
        } else {
            $title = $pageName;
        }
 
        if ( !$user ) {
            $user = static::getTestSysop()->getUser();
        }
        $comment = __METHOD__ . ': Sample page for unit test.';
 
        $page = WikiPage::factory( $title );
        $page->doEditContent( ContentHandler::makeContent( $text, $title ), $comment, 0, false, $user );
 
        return [
            'title' => $title,
            'id' => $page->getId(),
        ];
    }
 
    public function addDBDataOnce() {
    }
 
    public function addDBData() {
    }
 
    protected function addCoreDBData() {
        if ( $this->db->getType() == 'oracle' ) {
            # Insert 0 user to prevent FK violations
            # Anonymous user
            if ( !$this->db->selectField( 'user', '1', [ 'user_id' => 0 ] ) ) {
                $this->db->insert( 'user', [
                    'user_id' => 0,
                    'user_name' => 'Anonymous' ], __METHOD__, [ 'IGNORE' ] );
            }
 
            # Insert 0 page to prevent FK violations
            # Blank page
            if ( !$this->db->selectField( 'page', '1', [ 'page_id' => 0 ] ) ) {
                $this->db->insert( 'page', [
                    'page_id' => 0,
                    'page_namespace' => 0,
                    'page_title' => ' ',
                    'page_restrictions' => null,
                    'page_is_redirect' => 0,
                    'page_is_new' => 0,
                    'page_random' => 0,
                    'page_touched' => $this->db->timestamp(),
                    'page_latest' => 0,
                    'page_len' => 0 ], __METHOD__, [ 'IGNORE' ] );
            }
        }
 
        SiteStatsInit::doPlaceholderInit();
 
        User::resetIdByNameCache();
 
        // Make sysop user
        $user = static::getTestSysop()->getUser();
 
        // Make 1 page with 1 revision
        $page = WikiPage::factory( Title::newFromText( 'UTPage' ) );
        if ( $page->getId() == 0 ) {
            $page->doEditContent(
                new WikitextContent( 'UTContent' ),
                'UTPageSummary',
                EDIT_NEW | EDIT_SUPPRESS_RC,
                false,
                $user
            );
            // an edit always attempt to purge backlink links such as history
            // pages. That is unnecessary.
            JobQueueGroup::singleton()->get( 'htmlCacheUpdate' )->delete();
            // WikiPages::doEditUpdates randomly adds RC purges
            JobQueueGroup::singleton()->get( 'recentChangesUpdate' )->delete();
 
            // doEditContent() probably started the session via
            // User::loadFromSession(). Close it now.
            if ( session_id() !== '' ) {
                session_write_close();
                session_id( '' );
            }
        }
    }
 
    public static function teardownTestDB() {
        global $wgJobClasses;
 
        if ( !self::$dbSetup ) {
            return;
        }
 
        Hooks::run( 'UnitTestsBeforeDatabaseTeardown' );
 
        foreach ( $wgJobClasses as $type => $class ) {
            // Delete any jobs under the clone DB (or old prefix in other stores)
            JobQueueGroup::singleton()->get( $type )->delete();
        }
 
        // T219673: close any connections from code that failed to call reuseConnection()
        // or is still holding onto a DBConnRef instance (e.g. in a singleton).
        MediaWikiServices::getInstance()->getDBLoadBalancerFactory()->closeAll();
        CloneDatabase::changePrefix( self::$oldTablePrefix );
 
        self::$oldTablePrefix = false;
        self::$dbSetup = false;
    }
 
    protected static function setupDatabaseWithTestPrefix(
        IMaintainableDatabase $db,
        $prefix = null
    ) {
        if ( $prefix === null ) {
            $prefix = self::getTestPrefixFor( $db );
        }
 
        if ( ( $db->getType() == 'oracle' || !self::$useTemporaryTables ) && self::$reuseDB ) {
            $db->tablePrefix( $prefix );
            return false;
        }
 
        if ( !isset( $db->_originalTablePrefix ) ) {
            $oldPrefix = $db->tablePrefix();
 
            if ( $oldPrefix === $prefix ) {
                // table already has the correct prefix, but presumably no cloned tables
                $oldPrefix = self::$oldTablePrefix;
            }
 
            $db->tablePrefix( $oldPrefix );
            $tablesCloned = self::listTables( $db );
            $dbClone = new CloneDatabase( $db, $tablesCloned, $prefix, $oldPrefix );
            $dbClone->useTemporaryTables( self::$useTemporaryTables );
 
            $dbClone->cloneTableStructure();
 
            $db->tablePrefix( $prefix );
            $db->_originalTablePrefix = $oldPrefix;
        }
 
        return true;
    }
 
    public function setupAllTestDBs() {
        global $wgDBprefix;
 
        self::$oldTablePrefix = $wgDBprefix;
 
        $testPrefix = $this->dbPrefix();
 
        // switch to a temporary clone of the database
        self::setupTestDB( $this->db, $testPrefix );
 
        if ( self::isUsingExternalStoreDB() ) {
            self::setupExternalStoreTestDBs( $testPrefix );
        }
 
        // NOTE: Change the prefix in the LBFactory and $wgDBprefix, to prevent
        // *any* database connections to operate on live data.
        CloneDatabase::changePrefix( $testPrefix );
    }
 
    public static function setupTestDB( IMaintainableDatabase $db, $prefix ) {
        if ( self::$dbSetup ) {
            return;
        }
 
        if ( $db->tablePrefix() === $prefix ) {
            throw new MWException(
                'Cannot run unit tests, the database prefix is already "' . $prefix . '"' );
        }
 
        // TODO: the below should be re-written as soon as LBFactory, LoadBalancer,
        // and Database no longer use global state.
 
        self::$dbSetup = true;
 
        if ( !self::setupDatabaseWithTestPrefix( $db, $prefix ) ) {
            return;
        }
 
        // Assuming this isn't needed for External Store database, and not sure if the procedure
        // would be available there.
        if ( $db->getType() == 'oracle' ) {
            $db->query( 'BEGIN FILL_WIKI_INFO; END;', __METHOD__ );
        }
 
        Hooks::run( 'UnitTestsAfterDatabaseSetup', [ $db, $prefix ] );
    }
 
    protected static function setupExternalStoreTestDBs( $testPrefix = null ) {
        $connections = self::getExternalStoreDatabaseConnections();
        foreach ( $connections as $dbw ) {
            self::setupDatabaseWithTestPrefix( $dbw, $testPrefix );
        }
    }
 
    protected static function getExternalStoreDatabaseConnections() {
        global $wgDefaultExternalStore;
 
        $externalStoreDB = ExternalStore::getStoreObject( 'DB' );
        $defaultArray = (array)$wgDefaultExternalStore;
        $dbws = [];
        foreach ( $defaultArray as $url ) {
            if ( strpos( $url, 'DB://' ) === 0 ) {
                list( $proto, $cluster ) = explode( '://', $url, 2 );
                // Avoid getMaster() because setupDatabaseWithTestPrefix()
                // requires Database instead of plain DBConnRef/IDatabase
                $dbws[] = $externalStoreDB->getMaster( $cluster );
            }
        }
 
        return $dbws;
    }
 
    protected static function isUsingExternalStoreDB() {
        global $wgDefaultExternalStore;
        if ( !$wgDefaultExternalStore ) {
            return false;
        }
 
        $defaultArray = (array)$wgDefaultExternalStore;
        foreach ( $defaultArray as $url ) {
            if ( strpos( $url, 'DB://' ) === 0 ) {
                return true;
            }
        }
 
        return false;
    }
 
    protected function ensureMockDatabaseConnection( IDatabase $db ) {
        if ( $db->tablePrefix() !== $this->dbPrefix() ) {
            throw new LogicException(
                'Trying to delete mock tables, but table prefix does not indicate a mock database.'
            );
        }
    }
 
    private static $schemaOverrideDefaults = [
        'scripts' => [],
        'create' => [],
        'drop' => [],
        'alter' => [],
    ];
 
    protected function getSchemaOverrides( IMaintainableDatabase $db ) {
        return [];
    }
 
    private function undoSchemaOverrides( IMaintainableDatabase $db, $oldOverrides ) {
        $this->ensureMockDatabaseConnection( $db );
 
        $oldOverrides = $oldOverrides + self::$schemaOverrideDefaults;
        $originalTables = $this->listOriginalTables( $db );
 
        // Drop tables that need to be restored or removed.
        $tablesToDrop = array_merge( $oldOverrides['create'], $oldOverrides['alter'] );
 
        // Restore tables that have been dropped or created or altered,
        // if they exist in the original schema.
        $tablesToRestore = array_merge( $tablesToDrop, $oldOverrides['drop'] );
        $tablesToRestore = array_intersect( $originalTables, $tablesToRestore );
 
        if ( $tablesToDrop ) {
            $this->dropMockTables( $db, $tablesToDrop );
        }
 
        if ( $tablesToRestore ) {
            $this->recloneMockTables( $db, $tablesToRestore );
 
            // Reset the restored tables, mainly for the side effect of
            // re-calling $this->addCoreDBData() if necessary.
            $this->resetDB( $db, $tablesToRestore );
        }
    }
 
    private function setUpSchema( IMaintainableDatabase $db ) {
        // Undo any active overrides.
        $oldOverrides = $db->_schemaOverrides ?? self::$schemaOverrideDefaults;
 
        if ( $oldOverrides['alter'] || $oldOverrides['create'] || $oldOverrides['drop'] ) {
            $this->undoSchemaOverrides( $db, $oldOverrides );
            unset( $db->_schemaOverrides );
        }
 
        // Determine new overrides.
        $overrides = $this->getSchemaOverrides( $db ) + self::$schemaOverrideDefaults;
 
        $extraKeys = array_diff(
            array_keys( $overrides ),
            array_keys( self::$schemaOverrideDefaults )
        );
 
        if ( $extraKeys ) {
            throw new InvalidArgumentException(
                'Schema override contains extra keys: ' . var_export( $extraKeys, true )
            );
        }
 
        if ( !$overrides['scripts'] ) {
            // no scripts to run
            return;
        }
 
        if ( !$overrides['create'] && !$overrides['drop'] && !$overrides['alter'] ) {
            throw new InvalidArgumentException(
                'Schema override scripts given, but no tables are declared to be '
                . 'created, dropped or altered.'
            );
        }
 
        $this->ensureMockDatabaseConnection( $db );
 
        // Drop the tables that will be created by the schema scripts.
        $originalTables = $this->listOriginalTables( $db );
        $tablesToDrop = array_intersect( $originalTables, $overrides['create'] );
 
        if ( $tablesToDrop ) {
            $this->dropMockTables( $db, $tablesToDrop );
        }
 
        // Run schema override scripts.
        foreach ( $overrides['scripts'] as $script ) {
            $db->sourceFile(
                $script,
                null,
                null,
                __METHOD__,
                function ( $cmd ) {
                    return $this->mungeSchemaUpdateQuery( $cmd );
                }
            );
        }
 
        $db->_schemaOverrides = $overrides;
    }
 
    private function mungeSchemaUpdateQuery( $cmd ) {
        return self::$useTemporaryTables
            ? preg_replace( '/\bCREATE\s+TABLE\b/i', 'CREATE TEMPORARY TABLE', $cmd )
            : $cmd;
    }
 
    private function dropMockTables( IMaintainableDatabase $db, array $tables ) {
        $this->ensureMockDatabaseConnection( $db );
 
        foreach ( $tables as $tbl ) {
            $tbl = $db->tableName( $tbl );
            $db->query( "DROP TABLE IF EXISTS $tbl", __METHOD__ );
        }
    }
 
    private function listOriginalTables( IMaintainableDatabase $db ) {
        if ( !isset( $db->_originalTablePrefix ) ) {
            throw new LogicException( 'No original table prefix know, cannot list tables!' );
        }
 
        $originalTables = $db->listTables( $db->_originalTablePrefix, __METHOD__ );
 
        $unittestPrefixRegex = '/^' . preg_quote( $this->dbPrefix(), '/' ) . '/';
        $originalPrefixRegex = '/^' . preg_quote( $db->_originalTablePrefix, '/' ) . '/';
 
        $originalTables = array_filter(
            $originalTables,
            function ( $pt ) use ( $unittestPrefixRegex ) {
                return !preg_match( $unittestPrefixRegex, $pt );
            }
        );
 
        $originalTables = array_map(
            function ( $pt ) use ( $originalPrefixRegex ) {
                return preg_replace( $originalPrefixRegex, '', $pt );
            },
            $originalTables
        );
 
        return array_unique( $originalTables );
    }
 
    private function recloneMockTables( IMaintainableDatabase $db, array $tables ) {
        $this->ensureMockDatabaseConnection( $db );
 
        if ( !isset( $db->_originalTablePrefix ) ) {
            throw new LogicException( 'No original table prefix know, cannot restore tables!' );
        }
 
        $originalTables = $this->listOriginalTables( $db );
        $tables = array_intersect( $tables, $originalTables );
 
        $dbClone = new CloneDatabase( $db, $tables, $db->tablePrefix(), $db->_originalTablePrefix );
        $dbClone->useTemporaryTables( self::$useTemporaryTables );
 
        $dbClone->cloneTableStructure();
    }
 
    private function resetDB( $db, $tablesUsed ) {
        if ( $db ) {
            $userTables = [ 'user', 'user_groups', 'user_properties', 'actor' ];
            $pageTables = [
                'page', 'revision', 'ip_changes', 'revision_comment_temp', 'comment', 'archive',
                'revision_actor_temp', 'slots', 'content', 'content_models', 'slot_roles',
            ];
            $coreDBDataTables = array_merge( $userTables, $pageTables );
 
            // If any of the user or page tables were marked as used, we should clear all of them.
            if ( array_intersect( $tablesUsed, $userTables ) ) {
                $tablesUsed = array_unique( array_merge( $tablesUsed, $userTables ) );
                TestUserRegistry::clear();
 
                // Reset $wgUser, which is probably 127.0.0.1, as its loaded data is probably not valid
                // @todo Should we start setting $wgUser to something nondeterministic
                //  to encourage tests to be updated to not depend on it?
                global $wgUser;
                $wgUser->clearInstanceCache( $wgUser->mFrom );
            }
            if ( array_intersect( $tablesUsed, $pageTables ) ) {
                $tablesUsed = array_unique( array_merge( $tablesUsed, $pageTables ) );
            }
 
            // Postgres, Oracle, and MSSQL all use mwuser/pagecontent
            // instead of user/text. But Postgres does not remap the
            // table name in tableExists(), so we mark the real table
            // names as being used.
            if ( $db->getType() === 'postgres' ) {
                if ( in_array( 'user', $tablesUsed ) ) {
                    $tablesUsed[] = 'mwuser';
                }
                if ( in_array( 'text', $tablesUsed ) ) {
                    $tablesUsed[] = 'pagecontent';
                }
            }
 
            foreach ( $tablesUsed as $tbl ) {
                $this->truncateTable( $tbl, $db );
            }
 
            if ( array_intersect( $tablesUsed, $coreDBDataTables ) ) {
                // Reset services that may contain information relating to the truncated tables
                $this->overrideMwServices();
                // Re-add core DB data that was deleted
                $this->addCoreDBData();
            }
        }
    }
 
    protected function truncateTable( $tableName, IDatabase $db = null ) {
        if ( !$db ) {
            $db = $this->db;
        }
 
        if ( !$db->tableExists( $tableName ) ) {
            return;
        }
 
        $truncate = in_array( $db->getType(), [ 'oracle', 'mysql' ] );
 
        if ( $truncate ) {
            $db->query( 'TRUNCATE TABLE ' . $db->tableName( $tableName ), __METHOD__ );
        } else {
            $db->delete( $tableName, '*', __METHOD__ );
        }
 
        if ( $db instanceof DatabasePostgres || $db instanceof DatabaseSqlite ) {
            // Reset the table's sequence too.
            $db->resetSequenceForTable( $tableName, __METHOD__ );
        }
 
        // re-initialize site_stats table
        if ( $tableName === 'site_stats' ) {
            SiteStatsInit::doPlaceholderInit();
        }
    }
 
    private static function unprefixTable( &$tableName, $ind, $prefix ) {
        $tableName = substr( $tableName, strlen( $prefix ) );
    }
 
    private static function isNotUnittest( $table ) {
        return strpos( $table, self::DB_PREFIX ) !== 0;
    }
 
    public static function listTables( IMaintainableDatabase $db ) {
        $prefix = $db->tablePrefix();
        $tables = $db->listTables( $prefix, __METHOD__ );
 
        if ( $db->getType() === 'mysql' ) {
            static $viewListCache = null;
            if ( $viewListCache === null ) {
                $viewListCache = $db->listViews( null, __METHOD__ );
            }
            // T45571: cannot clone VIEWs under MySQL
            $tables = array_diff( $tables, $viewListCache );
        }
        array_walk( $tables, [ __CLASS__, 'unprefixTable' ], $prefix );
 
        // Don't duplicate test tables from the previous fataled run
        $tables = array_filter( $tables, [ __CLASS__, 'isNotUnittest' ] );
 
        if ( $db->getType() == 'sqlite' ) {
            $tables = array_flip( $tables );
            // these are subtables of searchindex and don't need to be duped/dropped separately
            unset( $tables['searchindex_content'] );
            unset( $tables['searchindex_segdir'] );
            unset( $tables['searchindex_segments'] );
            $tables = array_flip( $tables );
        }
 
        return $tables;
    }
 
    public function copyTestData( IDatabase $source, IDatabase $target ) {
        if ( $this->db->getType() === 'sqlite' ) {
            // SQLite uses a non-temporary copy of the searchindex table for testing,
            // which gets deleted and re-created when setting up the secondary connection,
            // causing "Error 17" when trying to copy the data. See T191863#4130112.
            throw new RuntimeException(
                'Setting up a secondary database connection with test data is currently not'
                . 'with SQLite. You may want to use markTestSkippedIfDbType() to bypass this issue.'
            );
        }
 
        $tables = self::listOriginalTables( $source );
 
        foreach ( $tables as $table ) {
            $res = $source->select( $table, '*', [], __METHOD__ );
            $allRows = [];
 
            foreach ( $res as $row ) {
                $allRows[] = (array)$row;
            }
 
            $target->insert( $table, $allRows, __METHOD__, [ 'IGNORE' ] );
        }
    }
 
    protected function checkDbIsSupported() {
        if ( !in_array( $this->db->getType(), $this->supportedDBs ) ) {
            throw new MWException( $this->db->getType() . " is not currently supported for unit testing." );
        }
    }
 
    public function getCliArg( $offset ) {
        return $this->cliArgs[$offset] ?? null;
    }
 
    public function setCliArg( $offset, $value ) {
        $this->cliArgs[$offset] = $value;
    }
 
    public function hideDeprecated( $function ) {
        Wikimedia\suppressWarnings();
        wfDeprecated( $function );
        Wikimedia\restoreWarnings();
    }
 
    protected function assertSelect(
        $table, $fields, $condition, array $expectedRows, array $options = [], array $join_conds = []
    ) {
        if ( !$this->needsDB() ) {
            throw new MWException( 'When testing database state, the test cases\'s needDB()' .
                ' method should return true. Use @group Database or $this->tablesUsed.' );
        }
 
        $db = wfGetDB( DB_REPLICA );
 
        $res = $db->select(
            $table,
            $fields,
            $condition,
            wfGetCaller(),
            $options + [ 'ORDER BY' => $fields ],
            $join_conds
        );
        $this->assertNotEmpty( $res, "query failed: " . $db->lastError() );
 
        $i = 0;
 
        foreach ( $expectedRows as $expected ) {
            $r = $res->fetchRow();
            self::stripStringKeys( $r );
 
            $i += 1;
            $this->assertNotEmpty( $r, "row #$i missing" );
 
            $this->assertEquals( $expected, $r, "row #$i mismatches" );
        }
 
        $r = $res->fetchRow();
        self::stripStringKeys( $r );
 
        $this->assertFalse( $r, "found extra row (after #$i)" );
    }
 
    protected function arrayWrap( array $elements ) {
        return array_map(
            function ( $element ) {
                return [ $element ];
            },
            $elements
        );
    }
 
    protected function assertArrayEquals( array $expected, array $actual,
        $ordered = false, $named = false
    ) {
        if ( !$ordered ) {
            $this->objectAssociativeSort( $expected );
            $this->objectAssociativeSort( $actual );
        }
 
        if ( !$named ) {
            $expected = array_values( $expected );
            $actual = array_values( $actual );
        }
 
        call_user_func_array(
            [ $this, 'assertEquals' ],
            array_merge( [ $expected, $actual ], array_slice( func_get_args(), 4 ) )
        );
    }
 
    protected function assertHTMLEquals( $expected, $actual, $msg = '' ) {
        $expected = str_replace( '>', ">\n", $expected );
        $actual = str_replace( '>', ">\n", $actual );
 
        $this->assertEquals( $expected, $actual, $msg );
    }
 
    protected function objectAssociativeSort( array &$array ) {
        uasort(
            $array,
            function ( $a, $b ) {
                return serialize( $a ) <=> serialize( $b );
            }
        );
    }
 
    protected static function stripStringKeys( &$r ) {
        if ( !is_array( $r ) ) {
            return;
        }
 
        foreach ( $r as $k => $v ) {
            if ( is_string( $k ) ) {
                unset( $r[$k] );
            }
        }
    }
 
    protected function assertTypeOrValue( $type, $actual, $value = false, $message = '' ) {
        if ( $actual === $value ) {
            $this->assertTrue( true, $message );
        } else {
            $this->assertType( $type, $actual, $message );
        }
    }
 
    protected function assertType( $type, $actual, $message = '' ) {
        if ( class_exists( $type ) || interface_exists( $type ) ) {
            $this->assertInstanceOf( $type, $actual, $message );
        } else {
            $this->assertInternalType( $type, $actual, $message );
        }
    }
 
    protected function isWikitextNS( $ns ) {
        global $wgNamespaceContentModels;
 
        if ( isset( $wgNamespaceContentModels[$ns] ) ) {
            return $wgNamespaceContentModels[$ns] === CONTENT_MODEL_WIKITEXT;
        }
 
        return true;
    }
 
    protected function getDefaultWikitextNS() {
        global $wgNamespaceContentModels;
 
        static $wikitextNS = null; // this is not going to change
        if ( $wikitextNS !== null ) {
            return $wikitextNS;
        }
 
        // quickly short out on most common case:
        if ( !isset( $wgNamespaceContentModels[NS_MAIN] ) ) {
            return NS_MAIN;
        }
 
        // NOTE: prefer content namespaces
        $namespaces = array_unique( array_merge(
            MWNamespace::getContentNamespaces(),
            [ NS_MAIN, NS_HELP, NS_PROJECT ], // prefer these
            MWNamespace::getValidNamespaces()
        ) );
 
        $namespaces = array_diff( $namespaces, [
            NS_FILE, NS_CATEGORY, NS_MEDIAWIKI, NS_USER // don't mess with magic namespaces
        ] );
 
        $talk = array_filter( $namespaces, function ( $ns ) {
            return MWNamespace::isTalk( $ns );
        } );
 
        // prefer non-talk pages
        $namespaces = array_diff( $namespaces, $talk );
        $namespaces = array_merge( $namespaces, $talk );
 
        // check default content model of each namespace
        foreach ( $namespaces as $ns ) {
            if ( !isset( $wgNamespaceContentModels[$ns] ) ||
                $wgNamespaceContentModels[$ns] === CONTENT_MODEL_WIKITEXT
            ) {
                $wikitextNS = $ns;
 
                return $wikitextNS;
            }
        }
 
        // give up
        // @todo Inside a test, we could skip the test as incomplete.
        //        But frequently, this is used in fixture setup.
        throw new MWException( "No namespace defaults to wikitext!" );
    }
 
    protected function markTestSkippedIfNoDiff3() {
        global $wgDiff3;
 
        # This check may also protect against code injection in
        # case of broken installations.
        Wikimedia\suppressWarnings();
        $haveDiff3 = $wgDiff3 && file_exists( $wgDiff3 );
        Wikimedia\restoreWarnings();
 
        if ( !$haveDiff3 ) {
            $this->markTestSkipped( "Skip test, since diff3 is not configured" );
        }
    }
 
    protected function checkPHPExtension( $extName ) {
        $loaded = extension_loaded( $extName );
        if ( !$loaded ) {
            $this->markTestSkipped( "PHP extension '$extName' is not loaded, skipping." );
        }
 
        return $loaded;
    }
 
    protected function markTestSkippedIfDbType( $type ) {
        if ( $this->db->getType() === $type ) {
            $this->markTestSkipped( "The $type database type isn't supported for this test" );
        }
    }
 
    public static function wfResetOutputBuffersBarrier( $buffer ) {
        return $buffer;
    }
 
    protected function setTemporaryHook( $hookName, $handler ) {
        $this->mergeMwGlobalArrayValue( 'wgHooks', [ $hookName => [ $handler ] ] );
    }
 
    protected function assertFileContains(
        $fileName,
        $actualData,
        $createIfMissing = false,
        $msg = ''
    ) {
        if ( $createIfMissing ) {
            if ( !file_exists( $fileName ) ) {
                file_put_contents( $fileName, $actualData );
                $this->markTestSkipped( 'Data file $fileName does not exist' );
            }
        } else {
            self::assertFileExists( $fileName );
        }
        self::assertEquals( file_get_contents( $fileName ), $actualData, $msg );
    }
 
    protected function editPage( $pageName, $text, $summary = '', $defaultNs = NS_MAIN ) {
        if ( !$this->needsDB() ) {
            throw new MWException( 'When testing which pages, the test cases\'s needsDB()' .
                ' method should return true. Use @group Database or $this->tablesUsed.' );
        }
 
        $title = Title::newFromText( $pageName, $defaultNs );
        $page = WikiPage::factory( $title );
 
        return $page->doEditContent( ContentHandler::makeContent( $text, $title ), $summary );
    }
 
    protected function revisionDelete(
        $rev, array $value = [ Revision::DELETED_TEXT => 1 ], $comment = ''
    ) {
        if ( is_int( $rev ) ) {
            $rev = Revision::newFromId( $rev );
        }
        RevisionDeleter::createList(
            'revision', RequestContext::getMain(), $rev->getTitle(), [ $rev->getId() ]
        )->setVisibility( [
            'value' => $value,
            'comment' => $comment,
        ] );
    }
}