SignIn a user for Unit test on laravel 5.4

How are you using actingAs; it takes a user instance rather than an id.

@tykus yep I use a user instance. The issue is that i have a model observer listening to the creating event and needs the authenticated user id. I am getting null

finally got it fixe, I used the auth() helper to log a user in the boot method.

Just use $this->be() ?