Trying to write a unit test for a service that dispaches a job

Hello,

I'm currently implementing an API (using Laravel 8.26.1) that has an endpoint which receives an array of e-mails and sends those e-mails asynchronously. Everything is working fine so far, but I'm willing to write a couple of unit tests for this behavior.

First, I have a controller with a send() method that calls a service like so:

class MyController extends Controller 
{
    private $service;

    public function __construct(MyService $service) {
        $this->service = $service;
    }

    public function send(Request $request) {
        $this->service->send($request->validated());
    }
}

Then the service has a single method send() which dispatches a job:

class MyService 
{    
    public function send($messages) {
        dispatch(new MyJob($messages));
    }
}

And finally the job that sends the e-mail:

class MyJob implements ShouldQueue
{
    use Dispatchable, InteractsWithQueue, Queueable, SerializesModels;

    private $messages;

    public function __construct($messages) {
        $this->messages = $messages;
    }

    public function handle() {
        foreach($this->messages as $message) {
            Mail::to($message['recipient'])->send(new MyMail($message));
        }
    }
}

Given all the structure above, my test so far looks like this:

class MyTest extends TestCase
{
    public function test_it_dispatches_job()
    {
        Queue::fake();

		$messages = [];
       
        (new MyService())->send($messages);

        Queue::assertPushed(MyJob::class);

    }
}

When I run the test I get the following error:

Illuminate\Contracts\Container\BindingResolutionException : Target [Illuminate\Contracts\Bus\Dispatcher] is not instantiable.

How can I update my code so I can test the behavior?

I also tried to dispatch the job in the service like MyJob::dispatch($messages) but I got the same error.

Thanks!