PHP使用命名空间扩展类致命错误

I have two classes. Bout in namespace test\bout\, and Art in namespace test\art.

namespace test\bout;
use test\art\Art;
class Bout extends Art{

    function __construct(){
        include_once 'Art.php';

        echo"boutique ";
        new Art();
    }
}
new Bout();

And after that :

namespace test\art;
class Art{

    function __construct(){
        echo "article";
    }
}

As soon as i put "extends Art" i have : Fatal error: Class 'test\art\Art' not found in /opt/lampp/htdocs/test/Boutique.php on line 4

Does it mean i'm not using "use test\art\Art;" correctly ?

thx all

I found it out !

namespace test\bout;
use test\art\Art;
**include __DIR__.'/article/Article.php';**
class Bout extends Art{...