Integration tests of web services and XHR

I am using Steak and Capybara to do my integration tests. I also would like to test the serialization output (webservices using XML and JSON format) of my models. The problem is that JSON is only available by using a XML HTTP Request. So Capybara's visit method does not work. It also seems that I don't have access to xhr method in my acceptance tests (not sure why, because I require the normal spec_helper.rb in my acceptance_helper.rb).

How do you test web services? Using the xhr method (after requiring it somehow)? A special method with Capybara? Something el开发者_StackOverflow中文版se?

I also have some custom serialization (beside the normal my_object.to_xml). I guess it is better to do that in the model tests. Would you then still test the web service output of those custom serializations?

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You can always create a "proxy" controller that makes requests to the web service and prints the result. It should be available only in test environment, obviously. Then your Capybara test visits the proxy and tests page content.