text: # -*- coding: utf-8 -*-
  '''preggy "null" (None) assertions.  For use with `expect()` (see `preggy.core`).
  '''
  
  # preggy assertions
  # https://github.com/heynemann/preggy
  
  # Licensed under the MIT license:
  # http://www.opensource.org/licenses/mit-license
  # Copyright (c) 2013 Bernardo Heynemann heynemann@gmail.com
  
  from __future__ import absolute_import
  from preggy import assertion
  
  
  @assertion
  def to_be_null(topic):
      '''Asserts that `topic` is `None`.'''
      if topic is not None:
          msg = 'Expected topic({0}) to be None'.format(topic)
          raise AssertionError(msg)
  
  
  @assertion
  def not_to_be_null(topic):
      '''Asserts that `topic` is NOT `None`.'''
      if topic is None:
          msg = 'Expected topic({0}) not to be None'.format(topic)
          raise AssertionError(msg)
  