title: How to suppress py.test internal deprecation warnings
body: <p>Is there a way to suppress the pytest's internal deprecation warnings?</p>
  
  <p>Context: I'm looking to evaluate the difficulty of porting a test suite from <code>nose</code> to <code>pytest</code>. The suite is fairly large and heavily uses <code>nose</code>-style <code>yield</code> based test generators.</p>
  
  <p>I'd like to first make sure the <em>existing</em> tests pass with pytest, and then maybe change test generators to <code>parameterized</code>.</p>
  
  <p>Just running <code>$ pytest path-to-test-folder</code> with pytest 3.0.4 is completely dominated by pages and pages of</p>
  
  <pre><code>WC1 ~repos/numpy/numpy/lib/tests/test_twodim_base.py yield tests are deprecated, and scheduled to be removed in pytest 4.0
  </code></pre>
  
  <p>Is there a way of turning these warnings off?</p>