Test::Unit test for valid url and implementation of valid url testing in Rails

gistfile1.rb

# Test in test/functional/sites_controller_test.rb
test "should contain a valid url" do
  @site.url = "random text"
  assert @site.invalid?
end

# Implementation in app/models/site.rb
class Site < ActiveRecord::Base
  validates_format_of :url, :with => /^(http|https):\/\/[a-z0-9]+([\-\.]{1}[a-z0-9]+)*\.[a-z]{2,5}(:[0-9]{1,5})?(\/.*)?$/ix
end