Unexpected passing Behat functional test

Hello,

I'm just doing functional tests for the first time using L5, Homestead, Behat3 and the Behat Laravel 5 Extension.

My test is very simple and it is stored in features/example.feature:

Feature: Sample

    In order to learn Behat
    As a programmer
    I need a simple url testing

    Scenario: Registration
        Given I am not logged in
        When I go to the registration form
        Then I will be automatically logged in

My FeatureContext.php contains the following functions:

    /**
     * @Given I am not logged in
     */
    public function iAmNotLoggedIn()
    {
        Auth::guest();
    }

    /**
     * @When I go to the registration form
     */
    public function iGoToTheRegistrationForm()
    {
       $this->visit(url('my/url'));
    }

    /**
     * @Then I will be automatically logged in
     */
    public function iWillBeAutomaticallyLoggedIn()
    {
        Auth::check();
    }

When I run behat, I expect the test to fail because the my/url url doesn't exists. However, it is all green...

Surely I'm doing something wrong, but I cannot find what. Can you give me some help?

Thank you very much,

Marco