# from the fixture YAML file (listings.yml):
bad_url:
  url: google

#from my unit test -
test "Should not save with bad url" do
  c = listings :bad_url
  assert !c.save
end

#from the model -
  validate :must_be_valid_url

  def must_be_valid_url
    uri = URI.parse(url)
    if uri.class != URI::HTTP
      errors.add(:url, 'Only HTTP protocol addresses can be used.')
    end
    rescue URI::InvalidURIError
      errors.add(:url, 'The format of the url is not valid.')
    end