Test and Strange Exception behaviour

I was in doubt so I've written this little test:

 /** @test **/
    function it_test_if_failed()
    {
        $this->get('/not-present');

        $this->assertTrue(true);
    }

Why the test in Laravel 5.6 returns green while the route is obviously not present? Why it not raise the exception? And how I can revert to the previous behaviour?

Thanks in advance

Guido