title: python unittest discover
body: <p>I don't understand something, with the python unittest discover.
  I made this project:</p>
  <pre><code>project/
      __init__.py
      src/
          __init__.py
          criteria.py
      tests/
          __init__.py
          criteria_test.py
  </code></pre>
  <p>And to be able to know if I loaded the test correctly I ensure myself to make it fail with the code below</p>
  <pre><code># coding: utf-8
  import unittest
  
  class TestCriteria(unittest.TestCase):
      def setUp(self):
          pass
      def test_criteriaFailure(self):
          self.assertTrue(False)
  </code></pre>
  <p>When I do the command in the command-line, I'm at the file project (the root of my packages), I guess everything can be imported.</p>
  <p>I tried:</p>
  <pre><code>python -m unittest discover
  python -m unittest discover -s tests -p '*_test.py'
  </code></pre>
  <p>but it always return me this output:</p>
  <pre><code>Ran 0 tests in 0.000s
  
  Ok
  </code></pre>
  <p>I'd like to understand how to use this feature (I'm using python3.2.3) without having to download and install Nose.</p>