CI4 Event methods not firing

Hi, I am trying to use Events to call some methods but the methods I'm calling aren't being fired.  Here is an example:
Config\Autoload.php:

Code:

public $classmap = [
        'MyClass' => APPPATH . 'Libraries/MyClass.php',
    ];

Libraries\MyClass:

Code:

namespace App\Libraries;

class MyClass
{
    public function testMethod() {
        var_dump("Test success");
        exit;
    }
}

Config\Events.php:

Code:

use App\Libraries\MyClass;

$MyClass = new MyClass();
Events::on('pre_system', [$MyClass, 'testMethod']);

I am expecting 'Test success' to print before the page is loaded, but currently the page is loading normally without printing 'Test success' at all and I can't seem to figure out what I'm doing wrong.

Thanks for your help!

It seems your code works fine, but you need to remove `exit`.
You should not use exit, because it terminates the framework working.

What if you write something to log file, not var_dump()?

ci-phpunit-test | CodeIgniter Testing Guide | CodeIgniter 3 to 4 Upgrade Helper

It seems your code works fine, but you need to remove `exit`.
You should not use exit, because it terminates the framework working.

What if you write something to log file, not var_dump()?

Thank you for your reply! Even if I take out the exit, this code still does not work for me.  'Test success' never gets printed on my page.

This is just a simplified example I am using, which I have tried in my current project without success.  I am upgrading my company's project from CI3 and my goal is to check a log file and a session file on the post_controller_constructor event and then write to a session file on the post_system event.  I am having trouble getting these methods to actually run on those events though, just like in my example

I was using version 4.1.8, once I upgraded the system files to version 4.2.1 the event methods started to work!