Support for allow_nil option to delegate_method matcher.

[alejandrodevs]

Hi everyone! I would like to add support for allow_nil option to delegate_method matcher.

it { should delegate_method(:deliver).to(:post_office).allow_nil(true) }

What do you think?

[maurogeorge]

Hi @AlejandroGutierrez I like the idea 👍

Just a note, I think it is better to not pass a param to allow_nil, but something like:

it { should delegate_method(:deliver).to(:post_office).allow_nil }

Take a look here where this was discussed.

I guess I never worked on this matcher code, but as you can see here the matcher works with different kinds of delegation(Fowardable, delegate and methods) so I think we will need to handle this across all delegation and not only on the delegate from Rails. Makes sense to you?

Could you please send a PR?

[alejandrodevs]

Yes, it makes sense!
I will work on this and will send a PR as soon as possible.
Thanks!

[mcmire]

Closing in favor of #751.