Stripe::Charge.list difficult to test in rspec 3.8

[KelseyDH]

Subject of the issue

I have a working rspec test for Stripe::Charge.list that works in rspec 3.7.1 but breaks in rspec 3.8.x. The maintainers of rspec say this is due to a problem with how the Stripe gem defines #hash on its objects.

Your environment

• Ruby version: 2.5.1
• rspec-expectations version: 3.8.1
• stripe 3.5.3

Steps to reproduce

The Stripe::Charge.list object id changes every time it is called, even if the data it gives back is the same. Meaning a call like this now fails:

            it "does not create a charge in stripe" do
              expect{ true }.to_not change{ Stripe::Charge.list }
            end

Expected behavior

The expected behaviour is that calls to two Stripe::Charge.list objects should consider not changed if the attributes within that object remain unchanged.

E.g.:

#<Stripe::ListObject:0x3feae3af47b4> JSON: {
  "object": "list",
  "data": [
    {"id":"test_ch_6","object":"charge","created":1366194027,"livemode":false,"paid":true,"amount":34800,"application_fee":null,"currency":"usd","destination":null,"fraud_details":{},"receipt_email":null,"receipt_number":null,"refunded":false,"shipping":{},"statement_descriptor":"Charge test_ch_6","status":"succeeded","source":{"object":"card","last4":"4242","type":"Visa","brand":"Visa","funding":"credit","exp_month":12,"exp_year":2013,"fingerprint":"3TQGpK9JoY1GgXPw","country":"US","name":"name","address_line1":null,"address_line2":null,"address_city":null,"address_state":null,"address_zip":null,"address_country":null,"cvc_check":null,"address_line1_check":null,"address_zip_check":null},"captured":true,"refunds":{"object":"list","total_count":0,"has_more":false,"url":"/v1/charges/test_ch_6/refunds","data":[]},"transfer":null,"balance_transaction":"test_txn_1","failure_message":null,"failure_code":null,"amount_refunded":0,"customer":{"id":"test_cus_3","email":"[email protected]","description":"an auto-generated stripe customer data mock","object":"customer","created":1372126710,"livemode":false,"delinquent":false,"discount":null,"account_balance":0,"currency":null,"sources":{"object":"list","total_count":1,"url":"/v1/customers/test_cus_3/sources","data":[{"id":"test_cc_2","object":"card","last4":"9191","type":"Visa","brand":"Visa","funding":"credit","exp_month":4,"exp_year":2018,"fingerprint":"wXWJT135mEK107G8","customer":"test_cus_3","country":"US","name":"Johnny App","address_line1":null,"address_line2":null,"address_city":null,"address_state":null,"address_zip":null,"address_country":null,"cvc_check":null,"address_line1_check":null,"address_zip_check":null,"tokenization_method":null,"number":null}]},"subscriptions":{"object":"list","total_count":0,"url":"/v1/customers/test_cus_3/subscriptions","data":[]},"default_source":"test_cc_2","metadata":{}},"invoice":null,"description":null,"dispute":null,"metadata":{}}
  ],
  "url": "/v1/hashs",
  "has_more": false
}

versus

#<Stripe::ListObject:0x3feae276ca0c> JSON: {
  "object": "list",
  "data": [
    {"id":"test_ch_6","object":"charge","created":1366194027,"livemode":false,"paid":true,"amount":34800,"application_fee":null,"currency":"usd","destination":null,"fraud_details":{},"receipt_email":null,"receipt_number":null,"refunded":false,"shipping":{},"statement_descriptor":"Charge test_ch_6","status":"succeeded","source":{"object":"card","last4":"4242","type":"Visa","brand":"Visa","funding":"credit","exp_month":12,"exp_year":2013,"fingerprint":"3TQGpK9JoY1GgXPw","country":"US","name":"name","address_line1":null,"address_line2":null,"address_city":null,"address_state":null,"address_zip":null,"address_country":null,"cvc_check":null,"address_line1_check":null,"address_zip_check":null},"captured":true,"refunds":{"object":"list","total_count":0,"has_more":false,"url":"/v1/charges/test_ch_6/refunds","data":[]},"transfer":null,"balance_transaction":"test_txn_1","failure_message":null,"failure_code":null,"amount_refunded":0,"customer":{"id":"test_cus_3","email":"[email protected]","description":"an auto-generated stripe customer data mock","object":"customer","created":1372126710,"livemode":false,"delinquent":false,"discount":null,"account_balance":0,"currency":null,"sources":{"object":"list","total_count":1,"url":"/v1/customers/test_cus_3/sources","data":[{"id":"test_cc_2","object":"card","last4":"9191","type":"Visa","brand":"Visa","funding":"credit","exp_month":4,"exp_year":2018,"fingerprint":"wXWJT135mEK107G8","customer":"test_cus_3","country":"US","name":"Johnny App","address_line1":null,"address_line2":null,"address_city":null,"address_state":null,"address_zip":null,"address_country":null,"cvc_check":null,"address_line1_check":null,"address_zip_check":null,"tokenization_method":null,"number":null}]},"subscriptions":{"object":"list","total_count":0,"url":"/v1/customers/test_cus_3/subscriptions","data":[]},"default_source":"test_cc_2","metadata":{}},"invoice":null,"description":null,"dispute":null,"metadata":{}}
  ],
  "url": "/v1/hashs",
  "has_more": false
}

Actual behavior

Instead the actual behaviour is that the .change matcher on 3.8 now detects this new object ID as a change when in 3.7.x it didn't.

---

I brought this problem up with rpec's maintainers, and they stated it's an issue that should be fixed within the Stripe gem itself. Quote:

"the best fix here would be to get a change into the stripe gem so that they do define #hash on these objects properly."

[brandur-stripe]

Alright, we're already overriding ==, so I think it makes sense to extend that equality to eql? and hash. Calling this a bug (i.e., as implied in that RSpec thread) isn't right though as no Ruby docs imply a requirement for classes to be hash key friendly, and two separate calls to .list are clearly going to produce a different set of objects. Opened a PR in #688.

BTW, I'd personally be a little cautious with this testing approach. By making checks dependent on list you're introducing an element of slowness and an element of brittleness from those extra network requests. You might consider mocking either via RSpec or webmock to check that no request to the Stripe API occurred.

[ob-stripe]

Fixed in 3.26.1.

[KelseyDH]

@ob-stripe @brandur-stripe Thanks for the lightning fast response!