How to resolve 'The expected [App\Events\UserRegistered] event was not dispatched.' error?

I have created a feature test to test the admin registration. When i run the testcases it gives me this error

1) Tests\Feature\Admin\RegisterTest::testValidRegistration The expected [App\Events\UserRegistered] event was not dispatched. Failed asserting that false is true.

/var/www/html/gas-backend/tests/Feature/Admin/RegisterTest.php:85

Below i have stated the admin registration test file and user registered event file

Admin/RegisterTest.php

$response->assertStatus(201);
        $response->assertJson($expectedResponse);
        $this->assertDatabaseHas('users', $expectedDatabaseRecord);
        Event::assertDispatched(UserRegistered::class);
        Notification::assertNotSentTo($user, RegistrationComplete::class);

UserRegistered.php

<?php

namespace App\Events;

use Illuminate\Broadcasting\Channel;
use Illuminate\Broadcasting\InteractsWithSockets;
use Illuminate\Broadcasting\PresenceChannel;
use Illuminate\Broadcasting\PrivateChannel;
use Illuminate\Contracts\Broadcasting\ShouldBroadcast;
use Illuminate\Foundation\Events\Dispatchable;
use Illuminate\Queue\SerializesModels;
use App\Models\User;

class UserRegistered
{
    use Dispatchable, InteractsWithSockets, SerializesModels;

    public $user;

    /**
     * Create a new event instance.
     *
     * @return void
     */
    public function __construct(User $user)
    {
        $this->user = $user;
    }

    /**
     * Get the channels the event should broadcast on.
     *
     * @return \Illuminate\Broadcasting\Channel|array
     */
    public function broadcastOn()
    {
        //return new PrivateChannel('channel-name');
    }
}

How should i resolve this error ?