assert_valid_asset plugin for Rails¶ ↑

assert_valid_asset is a plugin to validate your (X)HTML and CSS using the W3C Validator web service (validator.w3.org/) and the W3C CSS Validation Service (jigsaw.w3.org/css-validator) as part of your functional or unit tests. The css and html fragments are cached in $RAILS_ROOT/tmp/test/assets as are the results from the web service. This means that your tests will not be slowed down unless the output has changed.

The code started life as a few modifications to Scott Raymond’s assert_valid_markup (redgreenblu.com/svn/projects/assert_valid_markup/) and evolved to cache fragments and results in $RAILS_ROOT/tmp/test/assets rather than the system temp directory. Then the ability to validate CSS files was added. I also added the ability to skip checks if the “NONET” environment variable is set to “true”.

A more recent version made it possible to display the content with the line numbers by adding a line such as “self.display_invalid_content = true” into test_helper.rb in the Test::Unit::TestCase class.

The ability to automatically validate content generated as a result of a action can be enabled by adding the line “self.auto_validate = true” into test_helper.rb in the Test::Unit::TestCase class. This will generate content according to the mime type of content. (x)html will be passed to assert_valid_markup and css will be passed to assert_valid_css. You can also exclude specific tests by putting them into an an auto_validate_excludes or instead can choose to only include tests in list auto_validate_includes.

i.e. The following will automatically validate content generated in the test_foo and test_bar tests.

class Test::Unit::TestCase
  self.auto_validate = true
end

class FooControllerTest < Test::Unit::TestCase

  self.auto_validate_excludes = [:test_baz]

  def test_foo; ... ; end
  def test_bar; ... ; end
  def test_baz; ... ; end
end

i.e. The following will automatically validate content generated in the test_baz test.

class Test::Unit::TestCase
  self.auto_validate = true
end

class FooControllerTest < Test::Unit::TestCase

  self.auto_validate_includes = [:test_baz]

  def test_foo; ... ; end
  def test_bar; ... ; end
  def test_baz; ... ; end
end

HowTo Validate (X)HTML¶ ↑

# Calling the assertion with no parameters validates whatever is in @request.body,
# which is automatically set by the existing get/post/etc helpers. For example:

  class FooControllerTest < Test::Unit::TestCase
    def test_bar_markup
      get :bar
      assert_valid_markup
    end
  end

# Add a string parameter to the assertion to validate any random fragment. For example:

  class FooControllerTest < Test::Unit::TestCase
    def test_bar_markup
      assert_valid_markup "<div>Hello, world.</div>"
    end
  end

# For the ultimate in convenience, use the class-level method to validate a slew of
# actions in one line. Par exemple:

  class FooControllerTest < Test::Unit::TestCase
    assert_valid_markup :bar, :baz, :qux
  end

HowTo Validate CSS¶ ↑

# Pass a string parameter to the assertion to validate a css fragment. For example:

  class FooControllerTest < Test::Unit::TestCase
    def test_bar_css
      assert_valid_css(File.open("#{RAILS_ROOT}/public/stylesheets/bar.css",'rb').read)
    end
  end

# For the ultimate in convenience, use the class-level method to validate a slew of
# css files in one line. Assumes that the CSS files are relative to
# $RAILS_ROOT/public/stylesheets/ and end with '.css'. The following example validates
# $RAILS_ROOT/public/stylesheets/layout.css, $RAILS_ROOT/public/stylesheets/standard.css
# and $RAILS_ROOT/public/stylesheets/theme.css

  class FooControllerTest < Test::Unit::TestCase
    assert_valid_css_files 'layout', 'standard', 'theme'
  end

Details¶ ↑

License: Released under the MIT license.

Credits¶ ↑

• Scott Raymond <sco@scottraymond.net> for the initial version.

• Peter Donald <peter at realityforge dot org> to add validation of CSS files and fix caching.

• Simon Stapleton for inspiration to add who added support display_invalid_content.

• Clifford T. Matthews fix for ruby 1.8.5 and configuration of server endpoints.

• Tomasz Wegrzanowski for replacing class variables with class_inheritable_accessor.

• Cédric Deltheil for ensuring process_with_auto_validate returns the response.

• Nick Plante for fixing css validation.