random_case.ex

defmodule ExMachinaHelper do
  @doc """
  Converts all characters in the given string to a random case according to `:default` mode.

  Useful for writing tests where sorting is of importance.

  ## Examples
      iex> ExMachinaHelper.random_case("abcdef")
      "AbCdEf"

      iex> ExMachinaHelper.random_case("abcdef")
      "abcdef"

  """

  def random_case(string) when is_binary(string) do
    [:upcase, :downcase, :alternate, :none]
    |> Enum.random()
    |> case do
      :upcase ->
        String.upcase(string)

      :downcase ->
        String.downcase(string)

      :alternate ->
        string
        |> String.upcase()
        |> String.split("")
        |> Enum.map_every(2, &String.downcase/1)
        |> Enum.join()

      _ ->
        string
    end
  end
end