PhpSpec\Locator\PSR0\PSR0Locator::validatePsr0Classname PHP Method

    private function validatePsr0Classname($classname)
    {
        $pattern = '/\\A([a-zA-Z_\\x7f-\\xff][a-zA-Z0-9_\\x7f-\\xff]*[\\/\\\\]?)*[a-zA-Z_\\x7f-\\xff][a-zA-Z0-9_\\x7f-\\xff]*\\z/';
        if (!preg_match($pattern, $classname)) {
            throw new InvalidArgumentException(sprintf('String "%s" is not a valid class name.', $classname) . PHP_EOL . 'Please see reference document: ' . 'https://github.com/php-fig/fig-standards/blob/master/accepted/PSR-0.md');
        }
    }