How to lock the session with the desired values?

Question

PHPUnit

$session = \Mockery::mock(\Symfony\Component\HttpFoundation\Session\Session::class);

Here I get a mock session. But I would like to set the necessary values ​​\u200b\u200bin it, but for example, when I do this:

$session->shouldReceive('set', 'all', 'get')->once()->andReturnSelf();
$session->set('myKey', 'myValue');

then everything goes fine, but when I do $session->get('myKey'), then it returns me a Mockery object, instead of the expected myValue

Most likely I'm doing something wrong, maybe someone knows how to do it right ?