Broken test for payment in allocation_spec

[wsmoak]

Adding the Chargify::Payment resource for external payments in #128 has broken the assertion at

https://github.com/chargify/chargify_api_ares/blob/master/spec/resources/allocation_spec.rb#L87

expect(result.first.payment).to be_a Chargify::Allocation::Payment

Previously, it seems like ActiveResource was "inventing" a nested Chargify::Allocation::Payment (that doesn't really exist...). Now that there ​_is_​ a Chargify::Payment, it uses that.

A Chargify::Payment is an external payment, which records something that happened outside Chargify, like receiving a paper check in the mail. See: https://docs.chargify.com/api-payments

The 'Payment' within an 'Allocation' is really a Chargify::Transaction with a type of payment. See: https://docs.chargify.com/api-transactions

[wsmoak]

To restore the original behavior, it seems that defining a 'Payment' class inside 'Allocation' is enough to get ActiveResource to make the payment a Chargify::Allocation::Payment again. I'm still working with it to make sure that doesn't break anything else.

Thanks to @cmoel for help debugging this!

[wsmoak]

WIP on branch https://github.com/chargify/chargify_api_ares/tree/fix_allocation_spec2

This adds a Payment class inside Allocation, and ActiveResource "sees" it and uses it instead of the other Chargify::Payment.

The response differs slightly -- the Chargify::Allocation::Payment does not have the 'persisted' and 'prefix_options' attributes that seem to be on all the other objects whose classes extend from ActiveResource::Base.

Making the inner Payment class inherit from < Base does not make those attributes show up either.

I'm still working on getting the entire test suite (including the remote tests) to run locally to see if this breaks anything else.