Two fer

Resolving

defmodule TwoFer do
  @moduledoc """
  This is the TwoFer module.
  """
  
  @doc """
  Two-fer or 2-fer is short for two for one. One for you and one for me.
  """
  @spec two_fer(String.t()) :: String.t()
  def two_fer(name \\ "you") when is_bitstring name do
    "One for #{name}, one for me."
  end
end

Testing

ExUnit.start(auto_run: false)

defmodule TwoFerTest do
  use ExUnit.Case

  test "no name given" do
    assert TwoFer.two_fer() == "One for you, one for me."
  end

  @tag :pending
  test "a name given" do
    assert TwoFer.two_fer("Alice") == "One for Alice, one for me."
  end

  @tag :pending
  test "another name given" do
    assert TwoFer.two_fer("Bob") == "One for Bob, one for me."
  end

  @tag :pending
  test "when the argument is a number" do
    assert_raise FunctionClauseError, fn ->
      TwoFer.two_fer(10)
    end
  end

  @tag :pending
  test "when the argument is an atom" do
    assert_raise FunctionClauseError, fn ->
      TwoFer.two_fer(:bob)
    end
  end

  @tag :pending
  test "when the argument is a charlist" do
    assert_raise FunctionClauseError, fn ->
      refute TwoFer.two_fer(~c"Jon Snow")
    end
  end
end

ExUnit.run()