Rails titleize method port to Phoenix

string_helper_test.exs

defmodule MyApp.StringHelperTest do
  use MyApp.DataCase

  alias MyApp.StringHelpers

  describe "titleize/1 with valid string input" do
    test "returns titleized version of string" do
      assert "Man From The Boondocks" == StringHelpers.titleize("man from the boondocks")
      assert "The Man Without A Past" == StringHelpers.titleize("TheManWithoutAPast")
      assert "Raiders Of The Lost Ark" == StringHelpers.titleize("raiders_of_the_lost_ark")
      assert "String Ending With" == StringHelpers.titleize("string_ending_with_id")
    end
  end
end

string_helpers.ex

defmodule MyApp.StringHelpers do
  @moduledoc """
  Helper methods for working with strings
  """
  def titleize(str) do
    str
    |> Phoenix.Naming.underscore()
    |> Phoenix.Naming.humanize()
    |> String.replace(~r/\b(?<!\w['’`])[a-z]/, &String.capitalize/1)
  end
end