     files = %{
       included:
         files[:included]
+        |> List.wrap()
         |> Enum.map(&add_directory_to_file(&1, dir))
         |> Enum.uniq(),
       excluded:
         files[:excluded]
+        |> List.wrap()
         |> Enum.map(&add_directory_to_file(&1, dir))
         |> Enum.uniq()
     }

  @default_glob "**/*.{ex,exs}"
  @default_files_included [@default_glob]
  @default_files_excluded []

  alias Credo.Execution


  defp merge_boolean(_base, false), do: false
  defp merge_boolean(base, _), do: base

  defp merge_files_default(_base, [_head | _tail] = non_empty_list), do: non_empty_list
  defp merge_files_default(base, _), do: base

  defp merge_parse_timeout(_base, timeout) when is_integer(timeout), do: timeout
  defp merge_parse_timeout(base, _), do: base

