Explaining Laravel 5.1 issue with registering event handlers and testing with "expectsEvents"

[Preface: I resolved my root issue, this question is geared toward understanding why it occurred in the first place]

I have been debugging a test case where I register an event expectation via $this->expectsEvents(App\Events\MyTestEvent::class). The test kept giving me the following error, even though the event listener's code had run:

Exception: The following events were not fired: [App\Events\MyTestEvent]

Through lots of trial and error, it seems the problem occurs when using two different methods of registering event handlers (in EventServiceProvider.php) at the same time. See Case 1 below, which is my original code for registering my event handlers. If I move the auth.login handler to the $listen array (see Case 2), my test works and the problem is solved.

Questions:

• Am I doing something wrong in Case 1? or...
• Is this known / expected behavior? or ...
• Is this a bug in Laravel event handlers?

Thanks for your help and time!

---

Case 1 (original code, testing expectsEvent() for MyTestEvent fails)

class EventServiceProvider extends ServiceProvider
{
    protected $listen = [
        'App\Events\MyTestEvent' => [
            'App\Listeners\TestListener',
        ],
    ];

    public function boot(DispatcherContract $events)
    {
        parent::boot($events);

        Event::listen('auth.login', function()
        {
            Log::info("Login occurred");
        });
    }
}

---

Case 2 (modified code, expectsEvent() for MyTestEvent succeeds)

class EventServiceProvider extends ServiceProvider
{
    protected $listen = [
        'App\Events\MyTestEvent' => [
            'App\Listeners\TestListener',
        ],
        'auth.login' => [
            'App\Listeners\LoginListener',
        ],
    ];

    public function boot(DispatcherContract $events)
    {
        parent::boot($events);
    }
}

via Chebli Mohamed