I found this hard to read.. I read it as 'ask govuk delivery to create a notification success', wheras what it actually does is 'ask govuk delivery to stub create notification and respond with a successful response'. 

I think it would be easier to read without the stubbing helpers and just inline the webmock calls directly, or maybe to have helpers which generate the urls, body and canned responses according to parameters, e.g.

```
stub_request(:post, govuk_delivery_endpoint_url(:notifications))
  .with(govuk_delivery_body_json(feed_urls: feed_urls, subject: subject, body: body)))
  .to_return(govuk_delivery_error_response)
```