PHPUnit_TextUI_Command::handlePrinter PHP Method

    protected function handlePrinter($printerClass, $printerFile = '')
    {
        if (!class_exists($printerClass, false)) {
            if ($printerFile == '') {
                $printerFile = PHPUnit_Util_Filesystem::classNameToFilename($printerClass);
            }
            $printerFile = stream_resolve_include_path($printerFile);
            if ($printerFile) {
                require $printerFile;
            }
        }
        if (class_exists($printerClass)) {
            $class = new ReflectionClass($printerClass);
            if ($class->implementsInterface('PHPUnit_Framework_TestListener') && $class->isSubclassOf('PHPUnit_Util_Printer') && $class->isInstantiable()) {
                if ($class->isSubclassOf('PHPUnit_TextUI_ResultPrinter')) {
                    return $printerClass;
                }
                $outputStream = isset($this->arguments['stderr']) ? 'php://stderr' : null;
                return $class->newInstance($outputStream);
            }
        }
        $this->showError(sprintf('Could not use "%s" as printer.', $printerClass));
    }