Does Laravel 6 disable observers in factories / tests?

Ive just written an observer thats sends an e-mail whenever a user is created.

class UserObserver
{
    public function created(User $user)
    {
         Mail::to($user)->send(new UserAccountCreated(
            app('auth.password.broker')->createToken($user),
            $user
        ));
    }
}

I ran phpunit to test if my observer works, and it passed. However I was expecting to get an email for each time my tests create a user.

For example:

/** @test */
    public function an_admin_can_view_all_clients()
    {
        $user = factory(User::class)->create(['is_admin' => true]);
        $client = factory(Client::class)->create();
        $client2 = factory(Client::class)->create();

        $this->actingAs($user)->get(route('clients.index'))
            ->assertSuccessful()
            ->assertSee($client->name)
            ->assertSee($client2->name);
    }

I would expect an email to be sent when that factory creates the user. But I don't receive one in Mailtrap.

Just wondering if and where laravel disables my observer being triggered when my factory creates that user.