Output admin notice if persistent object caching is not present

[oscarssanchez]

Hi @westonruter,

Could you use this PR which addresses #960 ?

I was not sure where it was best to write the method in, so I opted to write it in class-amp-validation-utils but i'm open to your suggestions.

I'm also not sure if the output message would be good as it is now. I opted to include a link to https://codex.wordpress.org/Class_Reference/WP_Object_Cache#Persistent_Caching since users might not know what persistent object cache is and how to enable it.

Fixes #960.

[kienstra]

This looks good, @oscarssanchez. How about using a single printf() for this line and the one above?

[kienstra]

It's nice having $using here, as it's easy to see what you're testing. But it's probably not needed. It'd be cleaner to just pass the value straight to wp_using_ext_object_cache().

[kienstra]

This should probably go in the tearDown(), right above parent::tearDown().

[kienstra]

How about naming this persistent_object_caching_notice, as it relates to object caching?

[kienstra]

These nested conditionals could be on one line.

[kienstra]

$needle makes sense, in that you're searching for this. But a name like $text or $notice might be more descriptive.

[oscarssanchez]

Thanks for your feedback @kienstra .

I made the corresponding changes.

[westonruter]

I think we should eliminate the dismissal because as soon as the page reload the notice comes right back.

[westonruter]

@oscarssanchez once this change is made the PR will be good to merge.

[oscarssanchez]

Hi @westonruter,

Thanks for your comments, I just did the changes.