File exist problem with Coderay

existing spec that I'm trying to get to pass in rspec_api_documentation (total of 5 like this).rb

describe "xml data", :document => true do
    before do
      test_client.get "/xml"
    end

    it "should handle xml data" do
      test_client.last_response.headers["Content-Type"].should =~ /application\/xml/
    end

    it "should log the request" do
      example.metadata[:requests].first[:route].should == "/xml"
    end
  end

My addition to test_client.rb

require 'coderay'

module RspecApiDocumentation
  class TestClient < Struct.new(:session, :options)
    #...
    private
    def document_example(method, action, params)
      #...
      request_metadata[:response_body] = formatted_response_body(last_response.body, last_response.headers['Content-Type'])
      #...
    end

    #...
    
    def formatted_response_body(body, content_type)
      options = {}#{:line_numbers => :table}
      begin
        case content_type
          when /xml/
            CodeRay.scan(body, :xml).div(options)
          when /html/
            CodeRay.scan(body, :html).div(options)
          when /json/
            CodeRay.scan(JSON.pretty_generate(JSON.parse(body)), :json).div
          when /javascript/
            CodeRay.scan(JSON.pretty_generate(body), :javascript).div(options)
          when /image|jpg|jpeg|gif|png|bmp|binary/
            "<img src=\"data:binary/octet;base64,#{Base64.encode64(body)}\" />"
          else
            body
        end
      rescue
        last_response.body
      end
    end
end

The snippet from coderay where the JSON (and other) plugin gets loaded up.rb

def make_plugin_hash
      @plugin_map_loaded ||= false
      Hash.new do |h, plugin_id|
        id = validate_id(plugin_id)
        path = path_to id
        begin
          raise LoadError, "#{path} not found" unless File.exist? path #File.exist? returns false even though the file is there when running my spec
          require path
        rescue LoadError => boom
          if @plugin_map_loaded
            if h.has_key?(:default)
              warn '%p could not load plugin %p; falling back to %p' % [self, id, h[:default]]
              h[:default]
            else
              raise PluginNotFound, '%p could not load plugin %p: %s' % [self, id, boom]
            end
          else
            load_plugin_map
            h[plugin_id]
          end
        else
          # Plugin should have registered by now
          if h.has_key? id
            h[id]
          else
            raise PluginNotFound, "No #{self.name} plugin for #{id.inspect} found in #{path}."
          end
        end
      end
    end

require 'coderay' causes:

 CodeRay::PluginHost::PluginNotFound:
   CodeRay::Scanners could not load plugin :json: /Users/readwl/.rvm/gems/ruby-1.9.2-p180@rspecapidocumentation/gems/coderay-1.0.5/lib/coderay/scanners/json.rb not found