Update delete_files() helper function

[michalsn]

Description
Support for removing hidden folders. See: #3015

Checklist:

• Securely signed commits
• Component(s) with PHPdocs
• Unit testing, with >80% coverage
• User guide updated
• Conforms to style guide

[MGatner]

This is exactly what I was looking for! I looks good. My only thought is that it duplicates a fair amount of functionality from get_filenames(). Does it make sense to leverage that function to gather the files and just use this to delete them? Or is that kind of inter-dependence undesirable in helper functions, in case somewhere were to (say) overwrite them?

[michalsn]

The thing is that we need our files to be in a certain order so we can delete them and get_filenames() function doesn't give us that.

Of course, we can work on the result returned by get_filenames() but it won't be very pretty. I would stay with the current approach, even if these two functions are a bit similar.

[MGatner]

Good point! I’m happy with this one. I actually have a few projects I will go update once this is merged. 😋

[michalsn]

I'm not sure why Coveralls show decreased test coverage. I will say it's a mistake and merge.

[MGatner]

I’ve found the Coveralls CI to be unreliable on small PRs. Not worried about it.