Auth_OpenID_ServerError::getReturnTo PHP Méthode

    function getReturnTo()
    {
        if ($this->message && $this->message->hasKey(Auth_OpenID_OPENID_NS, 'return_to')) {
            return $this->message->getArg(Auth_OpenID_OPENID_NS, 'return_to');
        } else {
            return null;
        }
    }

 function test_noMessage()
 {
     $e = new Auth_OpenID_ServerError();
     $this->assertFalse($e->hasReturnTo());
     $this->assertEquals($e->whichEncoding(), null);
     $this->assertEquals($e->getReturnTo(), null);
 }