Live Doctests

OK

defmodule OKTest do
  @doc """
  Add two numbers

  ## Parameters

    - a: a number
    - b: a number

  ## Examples

  iex> OKTest.add(1, 1)
  2

  iex> OKTest.add(1.1, 2)
  3.1

  iex> OKTest.add("1", 2)
  ** (ArithmeticError) bad argument in arithmetic expression
  """
  @spec add(number(), number()) :: number()
  def add(a, b) do
    a + b
  end
end

NG

defmodule NGTest do
  @doc """
  Add two numbers

  ## Parameters

    - a: a number
    - b: a number

  ## Examples

  iex> NGTest.add(1, 1)
  3

  iex> NGTest.add(1.1, 2)
  3.3

  iex> NGTest.add("1", 2)
  ** (RuntimeError) error!!
  """
  @spec add(number(), number()) :: number()
  def add(a, b) do
    a + b
  end
end

Mixed

defmodule MixedTest do
  @doc """
  Add two numbers

  ## Parameters

    - a: a number
    - b: a number

  ## Examples

  iex> MixedTest.add(1, 1)
  2

  iex> MixedTest.add(1.1, 2)
  3.3

  iex> MixedTest.add("1", 2)
  ** (ArithmeticError) bad argument in arithmetic expression
  """
  @spec add(number(), number()) :: number()
  def add(a, b) do
    a + b
  end
end

Multi Line

defmodule MultiLine do
  @doc ~S"""
  Split text lines

  ## Parameters

    - str: text

  ## Examples

  iex> MultiLine.split("a\nb")
  ["a", "b"]

  iex> ~s(a
  ...>b
  ...>c)
  ...>|> MultiLine.split()
  ["a", "b", "c"]
  """
  @spec split(String.t()) :: list(String.t())
  def split(str) do
    str
    |> String.trim()
    |> String.split("\n")
  end
end

defmodule Words do
  @doc ~S"""
  Join words into multiline

  ## Parameters

    - words: list of words

  ## Examples

  iex> Words.join(["a", "b"])
  "a\nb"

  iex> Words.join(["a", "b", "c"])
  ~s(a
  b
  c)
  """
  @spec join(list(String.t())) :: String.t()
  def join(words) do
    Enum.join(words, "\n")
  end
end