 
   """
   defmacro refute({:match?, meta, [left, right]} = assertion) do
-    code   = escape_quoted(:refute, assertion)
+    code = escape_quoted(:refute, assertion)
     match? = {:match?, meta, [left, Macro.var(:right, __MODULE__)]}
-    pins   = collect_pins_from_pattern(left, __CALLER__.vars)
+    pins = collect_pins_from_pattern(left, __CALLER__.vars)
 
     quote do
       right = unquote(right)
+
       refute unquote(match?),
         right: right,
         expr: unquote(code),
         message: "match (match?) succeeded, but should have failed" <>
-                 ExUnit.Assertions.__pins__(unquote(pins))
+          ExUnit.Assertions.__pins__(unquote(pins))
     end
   end
 

  @doc false
  def __mailbox__(messages) do
    length = length(messages)
    mailbox =
      messages
      |> Enum.take(@max_mailbox_length)
      |> Enum.map_join(@indent, &inspect/1)
    mailbox_message(length, @indent <> mailbox)
  end

  @doc false
  def __pins__([]), do: ""
  def __pins__(pins) do
    content =
      pins
      |> Enum.reverse()
      |> Enum.map_join(@indent, fn {name, var} -> "#{name} = #{inspect(var)}" end)
    "\nThe following variables were pinned:" <> @indent <> content
  end

  defp mailbox_message(0, _mailbox), do: "\nThe process mailbox is empty."
  defp mailbox_message(length, mailbox) when length > 10 do
    "\nProcess mailbox:" <> mailbox <>
      "\nShowing only #{@max_mailbox_length} of #{length} messages."
  end
  defp mailbox_message(_length, mailbox) do
    "\nProcess mailbox:" <> mailbox
  end

            if Enum.any?(messages, unquote(pattern_finder)) do
              flunk(unquote(failure_message_hit))
            else
              flunk(
                unquote(failure_message_miss) <>
                  ExUnit.Assertions.__pins__(unquote(pins)) <>
                  ExUnit.Assertions.__mailbox__(messages)
              )
            end
        end

