map_compose_test.exs

defmodule MapComposeTest do
  use ExUnit.Case

  test "Enum.map function composition" do
    not_inner_composed =
      "hello world"
      |> String.split(" ")
      |> Enum.map(&String.reverse/1)
      |> Enum.map(&String.upcase/1)

   inner_composed =
     "hello world"
     |> String.split(" ")
     |> Enum.map(& String.reverse(&1) |> String.upcase())

   assert not_inner_composed == inner_composed
  end
end