class ChefSpec::Matchers::DoNothingMatcher

def failure_message
  if @resource
    message =  %{expected #{@resource} to do nothing, but the following }
    message << %{actions were performed:}
    message << %{\n\n}
    @resource.performed_actions.each do |action|
      message << %{  :#{action}}
    end
    message
  else
    message =  %{expected _something_ to do nothing, but the _something_ }
    message << %{you gave me was nil! If you are running a test like:}
    message << %{\n\n}
    message << %{  expect(_something_).to do_nothing}
    message << %{\n\n}
    message << %{make sure that `_something_` exists, because I got nil!}
    message
  end
end