A test model that doesn't use the Sluggable package.
Inheritance: extends Illuminate\Database\Eloquent\Model
 /**
  * Test that we don't try and slug models that don't implement Sluggable
  *
  * @test
  */
 public function testNonSluggableModels()
 {
     $post = new PostNotSluggable(['title' => 'My First Post']);
     $post->save();
     $this->assertEquals(null, $post->slug);
 }