title: Rails strange error => IndexError: string not matched
body: <p>I've got a very strange message error. I think it's not coming from Ruby but from the unix system.</p>
  
  <p>So, I have the following test file:</p>
  
  <pre><code>require File.dirname(__FILE__) + '/../test_helper' 
  
  class CatTest &lt; ActiveSupport::TestCase
      def test_truth
      assert true
     end
  end
  </code></pre>
  
  <p>So, nothing coming from YAML files in the Fixtures directory.</p>
  
  <p>When I run the test above with the command:</p>
  
  <pre><code>$ ruby ./test/unit/cat_test.rb
  </code></pre>
  
  <p>I get the very strange result:</p>
  
  <pre><code>Loaded suite ./test/unit/cat_test
  Started
  E
  Finished in 0.011252 seconds.
  
    1) Error:
  test_truth(CatTest):
  IndexError: string not matched
  
  
  1 tests, 0 assertions, 0 failures, 1 errors
  </code></pre>
  
  <p>I can't find the meaning of the error </p>
  
  <pre><code>IndexError: string not matched
  </code></pre>
  
  <p>But the most strange is that yesterday, It worked!</p>
  
  <p>Thank you very much for your help.</p>
  
  <p>Regards</p>
  
  <p>(I'm working under Ubuntu 9.04)</p>