03-input-output.exs

# http://elixir-lang.org/docs/stable/elixir/IO.html
# http://elixir-lang.org/docs/stable/elixir/File.html

defmodule CowInterrogator do

  # docstring are quite useful you can generate docs out of them
  # check: http://elixir-lang.org/getting-started/module-attributes.html
  # for more info
  @doc """
  Gets name from standard IO
  """
  def get_name do
    IO.gets("What is your name? ")
    |> String.trim
  end

  def get_cow_lover do
    IO.getn("Do you like cows? [y|n] ", 1)
  end

  def interrogate do
    name = get_name
    case String.downcase(get_cow_lover) do
      "y" ->
        IO.puts "Great! Here's a cow for you #{name}:"
        IO.puts cow_art
      "n" ->
        IO.puts "That's a shame, #{name}."
      _ ->
        IO.puts "You should have entered 'y' or 'n'."
    end
  end

  def cow_art do
    path = Path.expand("support/cow.txt", __DIR__)
    case File.read(path) do
      {:ok, art} -> art
      {:error, _} -> IO.puts "Error: cow.txt file not found"; System.halt(1)
    end
  end
end

ExUnit.start


defmodule InputOutputTest do
  use ExUnit.Case
  import String

  test "checks if cow_art returns string from support/cow.txt" do
    # this call checks if cow_art function returns art from txt file
    art = CowInterrogator.cow_art
    assert trim(art) |> first == "(" # first is implemented in String module
  end
end

# call interrogate performs most of the work
# asks about your name, your interests in cows
# and renders cow art
CowInterrogator.interrogate