fridge_server_test.ex

defmodule FridgeServer do
  use GenServer.Behaviour

  ### Public API
  def start_link(items) do
    {:ok, fridge} = :gen_server.start_link FridgeServer, items, []
    fridge
  end

  def store(fridge, item) do
    :gen_server.call(fridge, { :store, item })
  end

  def take(fridge, item) do
    :gen_server.call(fridge, {:take, item})
  end

  ### GenServer API

  def init(items) do
    { :ok, items }
  end

  def handle_call({:store, item}, _from, items) do
    {:reply, :ok, [item|items]}
  end
  def handle_call({:take, item}, _from, items) do
    case Enum.member?(items, item) do
      true ->
        {:reply, {:ok, item}, List.delete(items, item)}
      false ->
        {:reply, :not_found, items}
    end
  end
end

defmodule FridgeServerTest do
  use ExUnit.Case

  test "putting something into the fridge" do
    fridge = FridgeServer.start_link([])
    assert :ok == FridgeServer.store(fridge, :bacon)
  end

  test "removing something from the fridge" do
    fridge = FridgeServer.start_link([])
    FridgeServer.store(fridge, :bacon)
    assert {:ok, :bacon} == FridgeServer.take(fridge, :bacon)
  end

  test "taking something from the fridge that isn't in there" do
    fridge = FridgeServer.start_link([])
    assert :not_found == FridgeServer.take(fridge, :bacon)
  end
end