setPathInfo() public method

This method is mainly provided for testing purpose.
public setPathInfo ( string $value )
$value string the path info of the current request
 /**
  * Parses the URL and sets the language accordingly
  * @param \yii\web\Request $request
  * @return array|bool
  */
 public function parseRequest($request)
 {
     if ($this->enablePrettyUrl) {
         $pathInfo = $request->getPathInfo();
         $language = explode('/', $pathInfo)[0];
         $locale = ArrayHelper::getValue($this->aliases, $language, $language);
         if (in_array($language, $this->languages)) {
             $request->setPathInfo(substr_replace($pathInfo, '', 0, strlen($language) + 1));
             Yii::$app->language = $locale;
             static::$currentLanguage = $language;
         }
     } else {
         $params = $request->getQueryParams();
         $route = isset($params[$this->routeParam]) ? $params[$this->routeParam] : '';
         if (is_array($route)) {
             $route = '';
         }
         $language = explode('/', $route)[0];
         $locale = ArrayHelper::getValue($this->aliases, $language, $language);
         if (in_array($language, $this->languages)) {
             $route = substr_replace($route, '', 0, strlen($language) + 1);
             $params[$this->routeParam] = $route;
             $request->setQueryParams($params);
             Yii::$app->language = $locale;
             static::$currentLanguage = $language;
         }
     }
     return parent::parseRequest($request);
 }