title: Rspec expected failure declaration
body: <p>Is there a way to indicate that an rspec example is expected to fail?  </p>
  
  <p>My code includes a workaround for a bug in a 3rd party library.  I would like to include a check that the bug in the library exists. However a normal test might suggest to someone that the bug is desired behaviour, so rather than check for the bug existing, I want to check that it doesn't exist, and mark it as "expected failure". </p>
  
  <p>Then if the bug is later fixed, I'll know and will be able to take out the workaround.  </p>
  
  <p>Is there a way to do this in rspec?</p>