think\PhpunitHelper::guessPath PHP Method

    public function guessPath()
    {
        defined('DS') || define('DS', DIRECTORY_SEPARATOR);
        $vendorPath = dirname(dirname(__DIR__));
        $vendorParent = realpath(dirname($vendorPath));
        $rootPath = $this->getProjectRoot($vendorParent);
        $const = array();
        if ($rootPath) {
            $dir = dir($rootPath);
            $index = $basepath = false;
            while ($d = $dir->read()) {
                if ($d == 'index.php') {
                    $basepath = $rootPath;
                    $index = $rootPath . DS . 'index.php';
                    break;
                }
                if (file_exists($rootPath . DS . $d . DS . 'index.php')) {
                    $basepath = $rootPath . DS . $d;
                    $index = $rootPath . DS . $d . DS . 'index.php';
                    break;
                }
            }
            if ($index && $basepath) {
                $content = file_get_contents($index);
                if (preg_match_all('/define.*[\'"](\\w+)[\'"].*((?<=[\'"]).+(?=[\'"])|true|false)/im', $content, $matches, PREG_SET_ORDER)) {
                    foreach ($matches as $value) {
                        $const[$value[1]] = $value[2];
                    }
                    if (preg_match('{.*[\'"](.*ThinkPHP.php)[\'"]}', $content, $matches)) {
                        $think_path = dirname(realpath($basepath . DS . $matches[1]));
                        $const['THINK_PATH'] = $think_path;
                    }
                    if (!file_exists($const['APP_PATH'])) {
                        $const['APP_PATH'] = realpath($rootPath . DIRECTORY_SEPARATOR . $const['APP_PATH']);
                    }
                }
            }
            $const['ROOT_PATH'] = $rootPath;
        }
        return $const;
    }