module ChefSpec::Matchers
  class DoNothingMatcher
    def matches?(resource)
      @resource = resource

      if @resource
        ChefSpec::Coverage.cover!(@resource)

        actions = @resource.performed_actions
        actions.empty? || actions == [:nothing]
      else
        false
      end
    end

    def description
      "do nothing"
    end

    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

    def failure_message_when_negated
      if @resource
        message =  %{expected #{@resource} to do something, but no actions }
        message << %{were performed.}
        message
      else
        message =  %{expected _something_ to do something, but no actions }
        message << %{were performed.}
        message
      end
    end
  end
end