title: python unittests assertEqual print too much when it fails
body: <p>In a bunch of tests that I'm running using <code>nosetests</code>, an <code>assertEqual(a,b)</code> fails, <code>a</code> and <code>b</code> (pretty long strings) are printed verbatim filling the screen, obfuscating everything else. You can create similar situation by adding this to one of your test cases:</p>
  
  <pre><code>def test_my_long_strings(self): 
      self.assertEqual('a'*5000, 'b'*5000)
  </code></pre>
  
  <p>I tried setting <code>--verbosity=0</code> and <code>--debug-log=File</code>, but none of them had any effect, and the two strings are still printed on the screen. </p>
  
  <p>Is there anyway to shutup the <code>assertEqual</code> verbosity or redirect it to a separate file other than stderr (where test failures/passes are also reported)?</p>