text: """Testing the MongoDB core of cachier."""
  
  from cachier import cachier
  from cachier.core import MissingMongetter
  
  
  def test_bad_name():
      """Test that the appropriate exception is thrown when an invalid backend
      is given."""
  
      name = 'nope'
      try:
          @cachier(backend=name)
          def func():
              pass
      except ValueError as e:
          assert name in e.args[0]
      else:
          assert False
  
  
  def test_missing_mongetter():
      """Test that the appropriate exception is thrown when forgetting to
      specify the mongetter."""
      try:
          @cachier(backend='mongo', mongetter=None)
          def func():
              pass
      except MissingMongetter:
          assert True
      else:
          assert False
  