Session::setId not work in Laravel

I have code for testing :

public function setUp()
{
    parent::setUp();
    Session::setId('test');
}

public function testInitialize()
{
    echo Session::getId() . "\n";
}

and output in testInitialize function is:

bf7535b20443fd1302e2aa27a917a885b522e320

I assume that once laravel sets the session id it can't be set up again, but does somebody have snippet how to destroy session and set up again so the output in testInitialize() will be :

test

via Chebli Mohamed