Feature testing authentication with hidden property

How can I to test user authentication? My test:

public function successLogin()
    {
        $user = User::factory()->create(['login' => '123']);
        $user->makeVisible(['password']);
        $this->post(route('login'), $user->toArray());
        $this->assertAuthenticated(); // not asserts
    }

I saw this decision

$this->User->makeVisible(['password']);

But what is this proterty? Model? It is undefined.