morphToMany() Many-to-Many Polymorphic Relationship Test (Video-tag) - Testing Model Relationships in Laravel

morphToMany()_test.php

<?php
namespace Tests\Unit;

// ...

use App\Video;
use Tests\TestCase;
use Illuminate\Foundation\Testing\WithFaker;
use Illuminate\Foundation\Testing\RefreshDatabase;
use Illuminate\Support\Facades\Schema;

class VideosTest extends TestCase
{
    use RefreshDatabase, WithFaker;
    ...
    
    /** @test  */
    public function a_video_morphs_many_tags()
    {
        $this->assertInstanceOf('Illuminate\Database\Eloquent\Collection', $this->video->tags); 
    }
}