new_contents: #!/usr/bin/env python3
  """Functions for testing the Automaton abstract base class."""
  
  import nose.tools as nose
  
  from automata.base.automaton import Automaton
  
  
  def test_abstract_methods_not_implemented():
      """Should raise NotImplementedError when calling abstract methods."""
      with nose.assert_raises(NotImplementedError):
          Automaton.__init__(Automaton)
      with nose.assert_raises(NotImplementedError):
          Automaton.validate_self(Automaton)
      with nose.assert_raises(NotImplementedError):
          Automaton._validate_input_yield(Automaton, None)
  
subject: Add tests for abstract method NotImplementedError