RSpec2 JSON matcher

json_matcher.rb

# RSpec2 JSON Matcher for functional/controller tests
# Webrat usage example:
# 
# it "should be the JSON representation" do
#   get :show, id: object.id, format: :json
#   response.body.should be_json_eql object.to_json
# end

require 'rspec/expectations'

RSpec::Matchers.define :be_json_eql do | expected |
  match do | actual |
    @expected = decode(expected, 'expected')
    @actual = decode(actual, 'actual')
    @actual == @expected
  end

  failure_message_for_should do | actual |
    "expected\n#{actual}\n" +
    "to be JSON code equivalent to\n#{expected}\n" +
    "Difference:\n#{@expected.diff(@actual).inspect}"
  end

  failure_message_for_should_not do | actual |
      "expected\n#{actual}\n" +
      "to be JSON code different from\n#{expected}"
    end

  def decode(s, which)
    ActiveSupport::JSON.decode(s)
  rescue ActiveSupport::JSON.parse_error
    raise ArgumentError, "Invalid #{which} JSON string: #{s}"
  end
end

Most of the credit needs to go to Bill Burcham for his code in this thread. I just converted for Rspec2.