How do I compare xml output in a Cucumber step using a multiline string example?

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      | joe@example.com |
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>joe@example.com</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 开发者_如何学运维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

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

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)