MockSvgHandler::class, 'image/vnd.djvu' => MockDjVuHandler::class, 'application/ogg' => MockOggHandler::class, ]; public function __construct() { // override parent } protected function getHandlerClass( $type ) { if ( isset( self::$overrides[$type] ) ) { return self::$overrides[$type]; } return MockBitmapHandler::class; } }