PHPUnit how to write a Laravel Nova Observer test

Hi,

I would like to write a test for my CommentObserver. This observer is only registered in the NovaServiceProvider but not the AppServiceProvider. This means I cannot test my observer by using my own Controllers.

In my eyes I have 3 ways to test my observer:

Either performing a feature test by sending a post request to the Nova API
Mocking the observer by calling the function in the observer to check if the function perfoms as desired
Trying to register my observer on the fly in the AppServiceProvider, performing a request and deregistering the observer in the AppServiceProvider again.

I tried to find a solution for any of these 3 ways to test my observer but unfortunately I faild with any of them.

Problems:

For way 1 I always get a validation error and Nova tells me that my input is invalid.
For way 2 I fail at mocking the observer function (when mocking the observer I also need to fake an HTTP request)
For way 3 I didn't find any solution on how to register and deregister the oberserver on the fly at the AppServiceProvider

Do you guys have idea and solition on how I can test my CommentObserver (which is as written above only registered in my NovaServiceProvider).

Update: So, here is the code of my observer. I need to have an valid request to test my observer in order to have the ability to access the $request->input('images') variable. I do know I can also use $comment->content instead of request()->input('content') because $comment->content already contains the new content which is not saved it this point.

The reason why I need a valid request is that the variable images is not part of the Comment model. So I cannot use $comment->images because it simply doesn't exist. That's why I need to access the request input. What my observer is basically doing is to extract the base64 images from the content, saves them to the server and replaces them by an image link.

class CommentObserver
{
    public function updating(Comment $comment)
    {
        if (!request()->input('content')) {
            return;
        }

        if (request()->input('content') == $comment->getRawOriginal('content')) {
            return;
        }

        $images = request()->input('images');
        if(!is_array($images)) {
            $images = json_decode(request()->input('images'));
        }

        checkExistingImagesAndDeleteWhenNotFound($comment, request()->input('content'), 'comments', 'medium');
        $comment->content = addBase64ImagesToModelFromContent($comment, request()->input('content'), $images, 'comments', 'medium');
    }
}

This is my test so far. I choose way 1 but as described already this always leads to an validation error by the nova controller and I cannot figure out what is the error/what is missing or wrong.

class CommentObserverTest extends TestCase
{
    /** @test */
    public function it_test()
    {
        $user = User::factory()->create([
            'role_id' => Role::getIdByName('admin')
        ]);

        $product = Product::factory()->create();

        $comment = Comment::factory()->create(['user_id' => $user->id, 'content' => '<p>Das ist wirklich ein super Preis!</p>', 'commentable_type' => 'App\Models\Product', 'commentable_id' => $product->id]);

        $data = [
            'content' => '<p>Das ist wirklich ein HAMMER Preis!</p>',
            'contentDraftId' => '278350e2-1b6b-4009-b4a5-05b92aedaae6',
            'pageStatus' => PageStatus::getIdByStatus('publish'),
            'pageStatus_trashed' => false,
            'commentable' => $product->id,
            'commentable_type' => 'App\Models\Product',
            'commentable_trashed' => false,
            'user' => $user->id,
            'user_trashed' => false,
            '_method' => 'PUT',
            '_retrieved_at' => now()
        ];

        $this->actingAs($user);

        $response = $this->put('http://nova.mywebsiteproject.test/nova-api/comments/' . $comment->id, $data);

        dd($response->decodeResponseJson());

        $das = new CommentObserver();
    }
}

Kind regards and thank you