gistfile1.rb

# spec_helper.rb

module BoxMatcher
  class Box
    def initialize(name)
      @name = name
    end

    def matches?(actual)
      raise "You must supply a 'containing' attribute (.containing 'foo')" unless @contents

      @actual = actual

      # ___Here is where the real magic happens___
      # It is simply a regular expression that tests our
      # expectations (the rendered HTML from the 'box' method)
      # against what the response actually rendered
      # If it matches, we have a passing spec.

      @actual.body =~ /<div class="box"><span class="box_label">#{@name}:</span>.*#{@contents}.*n</div>/im
    end

    def containing(contents)
      @contents = contents
      self
    end

    def failure_message
      "expected response to have a box describing '#{@name}', but it didn't"
    end

    def negative_failure_message
      "expected response to not have a box describing '#{@name}', but it did"
    end
  end

  def have_box_named(name)
    Box.new(name)
  end

end

...

Spec::Runner.configure do |config|
  ...
  # Include our new Matcher module
  config.include BoxMatcher, :type => :view
end