How do I compare xml output in a Cucumber step usi

Question

Chargify has this Cucumber scenario in their docs.

Scenario: Retrieve a customer via my reference id (as an integer or simple string)
Given I have a customer with these attributes
  | reference | first_name | last_name | email           |
  | 7890      | Joe        | Blow      | [e-mail] |
When I send a GET request to https://[@subdomain].chargify.com/customers/lookup.xml?reference=7890
Then the response status should be "200 OK"
And the response should be the xml:
  """
  <?xml version="1.0" encoding="UTF-8"?>
  <customer>
    <id type="integer">`auto generated`</id>
    <first_name>Joe</first_name>
    <last_name>Blow</last_name>
    <email>[e-mail]</email>
    <organization>`your value`</organization>
    <reference>7890</reference>
    <created_at type="datetime">`auto generated`</created_at>
    <updated_at type="datetime">`auto generated`</updated_at>
  </customer>
  """

I'm trying to follow their approach in testing an API we're developing here, instead of checking for the tags one by one, like I we were doing before coming across this example.

So far no luck matching the response's output with the step's multiline string, due to formatting issues. Haven't found a way with Nokogiri nor with simple stripped string comparison.

Is there an elegant (and efficient) way to do this?

Update

Here's the cucumber step using Mark's solution:

Then /^I should see the following output$/ do |xml_output|
  response = Hash.from_xml(page.body)
  expected = Hash.from_xml(xml_output)  
  expected.diff(response).should == {}
end

Answer 1

You can use Hash.from_xml and then compare with Hash.diff. Comparing as hashes eliminates insignificant whitespace from messing up comparisons.

Answer 2

In case you don't want the dependency on ActiveSuport (for instance, if you are outside Rails), you might try the equivalent-xml gem. It allows you to write the above expectation as follows:

response = page.body
response.should be_equivalent_to(xml_output)