title: Cucumber/Capybara: check that a page does NOT have content?
body: <p>Using Cucumber and Capybara, is there a way to verify that a string is NOT present on a page?</p>
  
  <p>For example, how would I write the opposite of this step:</p>
  
  <pre><code>Then /^I should see "(.*?)"$/ do |arg1|
    page.should have_content(arg1)
  end
  </code></pre>
  
  <p>This passes if <code>arg1</code> is present. </p>
  
  <p>How would I write a step that <em>fails</em> if <code>arg1</code> is found?</p>