new_contents: import unittest
  
  from nose.tools import eq_
  import zookeeper
  
  
  class TestExceptions(unittest.TestCase):
      def _makeOne(self, *args, **kwargs):
          from kazoo.exceptions import err_to_exception
          return err_to_exception(*args, **kwargs)
  
      def test_error_translate(self):
          exc = self._makeOne(zookeeper.SYSTEMERROR)
          assert isinstance(exc, zookeeper.SystemErrorException)
  
      def test_error_with_message(self):
          exc = self._makeOne(zookeeper.NONODE, msg="oops")
          assert isinstance(exc, zookeeper.NoNodeException)
          eq_(str(exc), "no node: oops")
  
      def test_generic_error_code(self):
          exc = self._makeOne(-200)
          assert isinstance(exc, Exception)
  
      def test_zookeeper_ok(self):
          exc = self._makeOne(zookeeper.OK)
          eq_(exc, None)
  
      def test_not_error_code(self):
          exc = self._makeOne("this needs to be an int")
          assert isinstance(exc, Exception)
  
subject: Add complete exception unit tests.