title: py.test does not find tests under a class
body: <p>I am trying to create test classes that aren't unittest based.</p>
  
  <p>This method under this class</p>
  
  <pre><code>class ClassUnderTestTests:
  
      def test_something(self):
  </code></pre>
  
  <p>cannot be detected and run when you call py.test from the command line or when you run this test in PyCharm (it's on its own module).</p>
  
  <p>This</p>
  
  <pre><code>def test_something(self):
  </code></pre>
  
  <p>same method outside of a class can be detected and run.</p>
  
  <p>I'd like to group my tests under classes and unless I'm missing something I'm following the <a href="http://pytest.org/latest/getting-started.html">py.test spec</a> to do that.</p>
  
  <p>Environment: Windows 7, PyCharm with py.test set as the test runner.</p>