title: What is a good way to test a method that expects an HTML string?
body: <pre><code>foo.should_receive( :save ).with( html )
  </code></pre>
  
  <p>Where <code>html</code> is an HTML string, but I don't want to check against specific HTML because that would make the test brittle.</p>
  
  <p>Is there a way to check the length of the param that foo should receive? Is it possible to use a matcher or something like <code>html.should include '&lt;html'</code>?</p>
  
  <p>Working in RSpec.</p>