Tenderlove Making

Easy Markup Validation

Jun 12, 2009 @ 5:24 pm

I wanted a test helper that would assert that my XHTML was valid XHTML. So I wrote one and called it “markup_validity”. You can use it too, and I will show you how.

First, install the gem:

Then, use it in your tests:

require 'test/unit'
require 'rubygems'
require 'markup_validity'

class ValidHTML < Test::Unit::TestCase
  def test_i_can_has_valid_xhtml
    assert_xhtml_transitional xhtml_document
  end
end

Oh. You use RSpec? It supports that too:

require 'rubygems'
require 'markup_validity'

describe "my XHTML document" do
  it "can has transitional xhtml" do
    xhtml_document.should be_xhtml_transitional
  end
end

Debugging invalid markup can be a pain. MarkupValidity tries to give you helpful errors to make your life easier. Say you have an invalid piece of XHTML like this:

<html xmlns="http://www.w3.org/1999/xhtml">
  <head>
  </head>
  <body>
    <p>
      <p>
        Hello
      </p>
    </p>
  </body>
</html>

The error output from MarkupValidity will be this:

.Error on line: 2:
Element 'head': Missing child element(s). Expected is one of ( script, style, meta, link, object, isindex, title, base ).

1: <html xmlns="http://www.w3.org/1999/xhtml">
2:   <head>
3:   </head>
4:   <body>
5:     <p>

Error on line: 6:
Element 'p': This element is not expected. Expected is one of ( a, br, span, bdo, object, applet, img, map, iframe, tt ).

5:     <p>
6:       <p>
7:         Hello
8:       </p>
9:     </p>

MarkupValidity provides a few assertions for test/unit:

The methods provided for RSpec are quite similar:

MarkupValidity even works well with rails. Here is an example rails controller test:

require 'test_helper'
require 'markup_validity'

class AwesomeControllerTest < ActionController::TestCase
  test "valid markup" do
    get :new
    assert_xhtml_transitional @response.body
  end
end
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