1.  Calling the assertion with no parameters validates
2.  whatever is in @request.body, which is automatically
3.  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

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

class FooControllerTest < Test::Unit::TestCase
def test\_bar\_markup
assert\_valid\_markup "

<div>
Hello, world.

</div>
"
end
end

1.  For the ultimate in convenience, use the class-level
2.  method to validate a number of actions in one line.

class FooControllerTest &lt; Test::Unit::TestCase
assert\_valid\_markup :bar, :baz, :qux
end

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

class FooControllerTest < Test::Unit::TestCase
def test\_bar\_css
filename = “\#{RAILS\_ROOT}/public/stylesheets/bar.css”
assert\_valid\_css(File.open(filename ,‘rb’).read)
end
end

1.  For the ultimate in convenience, use the class-level
2.  method to validate a bunch of css files in one line.
3.  Assumes that the CSS files are relative to
4.  $RAILS\_ROOT/public/stylesheets/ and end with ‘.css’.
5.  The following example validates
6.  $RAILS\_ROOT/public/stylesheets/layout.css,
7.  $RAILS\_ROOT/public/stylesheets/standard.css and
8.  $RAILS\_ROOT/public/stylesheets/theme.css

class FooControllerTest < Test::Unit::TestCase
assert\_valid\_css\_files ‘layout’, ‘standard’, ‘theme’
end