Your PHPUnit test is the client, not the web application itself. Therefore, Auth :: check () should not return true. Instead, you can verify that you are on the correct page after clicking the button and that you see some kind of confirmation text:
public function a_user_can_log_in()
{
$user = factory(App\User::class)->create([
'email' => 'john@example.com',
'password' => bcrypt('testpass123')
]);
$this->visit(route('login'))
->type($user->email, 'email')
->type('testpass123', 'password')
->press('Login')
->see('Successfully logged in')
->onPage('/dashboard');
}
, . Auth:: check() - , , ..