Assert model was not made searchable

Question

I'm building a system to manage some articles for my company using Laravel and Laravel Scout with Algolia as the search backend.

One of the requirements states that whenever something in an article is changed, a backup is kept so we can prove that a certain information was displayed at a specific time.

I've implemented that by cloning the existing article with all its relationships before updating it. Here is the method on the Article model:

public function clone(array $relations = null, array $except = null) {
    if($relations) {
        $this->load($relations);
    }

    $replica = $this->replicate($except);
    $replica->save();

    $syncRelations = collect($this->relations)->only($relations);

    foreach($syncRelations as $relation => $models) {
        $replica->{$relation}()->sync($models);
    }

    return $replica;
}

The problem is the $replica->save() line. I need to save the model first, in order for it to have an ID when syncing the relationships.

But: The only thing preventing scout from indexing the model is if the model has its archived_at field set to any non-null value. But since this is a clone of the original model, this field is set to null as expected, and is only changed after the cloning procedure is done.

The problem: Scout is syncing the cloned model to Algolia, so I have duplicates there. I know how to solve this, by wrapping the clone call into the withoutSyncingToSearch (https://laravel.com/docs/5.6/scout#pausing-indexing) callback. But since this is rather important and the bug is already out there, I want to have a unit test backing me up that it was indeed not synced to Algolia. I don't have any idea how to test this though and searching for a way to test Scout only leads to answers that tell me not to test Scout, but rather that my model can be indexed etc.

The question: How do I create a Unittest that proves that the cloned model wasn't synced to Algolia?

At the moment I'm thinking about creating a custom Scout driver for testing, but it seems to be a total overkill for testing one single function.