title: Nose unable to find tests in ubuntu
body: <p>Is there any reason why Nose wouldn't be able to find tests in Ubuntu 9.04? </p>
  
  <p>I'm using nose 0.11.1 with python 2.5.4.<br>
  I can run tests only if I explicitly specify the filename. 
  If I don't specify the filename it just says, <strong>0 tests</strong>. </p>
  
  <p>The same project runs tests fine on my Mac, so I'm quite stumped!</p>