title: Parallel Test Execution hangs indefinitely for rspec
body: <p>I'm running my specs through parallel_tests on the capybara-webkit driver. I have the following ruby environment:</p>
  
  <pre><code> ruby -v
   ruby 1.9.3p125 (2012-02-16 revision 34643) [x86_64-darwin11.4.2]
  </code></pre>
  
  <p>Running through rvm on a gemset  which contains the following (truncated for capybara, rails, rspec, and parallel_tests for relevance. If seeing a larger swathe of my gemset would help, please let me know):</p>
  
  <pre><code> *** LOCAL GEMS ***
  
   ...
   capybara (1.1.2)
   parallel_tests (0.8.12)
   rails (3.2.11)
   rspec (2.11.0)
  </code></pre>
  
  <p>When I run my test suit on a single process with <code>rake spec</code>, all of my tests run to completion.
  However, when runnning through parallel_tests, the following happens:</p>
  
  <pre><code> 8 processes for 220 specs, ~ 27 specs per process
  </code></pre>
  
  <p>Whereafter the processes will eventually start coming back:</p>
  
  <pre><code> Finished in 11 minutes 15.76 seconds
   Finished in 11 minutes 28.89 seconds
  </code></pre>
  
  <p>But, after the first 6 processes come back, parallel_spec will hang indefinitely, never terminate, and never print output for the remaining 2 processes.</p>
  
  <p>I'm on a MacBook Pro running OS X Lion, with a 2.4GHz Intel i7.</p>
  
  <p>So my question is simple: Why is it hanging, how can I debug why its hanging, and how can I stop it from hanging and allow parallel_tests to run to completion?</p>