Property-Based Testing with PropEr, Erlang, and Elixir

Case Study: Bookstore

Introducing the Application

Script to initialize the database:

Elixir                code/Bookstore/elixir/bookstore/lib/bookstore/init.ex

defmodule Bookstore.Init do
  def main(_) do
    # See: https://www.postgresql.org/docs/9.6/static/server-start.html
    File.mkdir_p!("postgres/data/")
    stdout = IO.stream(:stdio, :line)

    IO.puts("initializing database structure...")
    System.cmd("initdb", ["-D", "postgres/data"], into: stdout)
    IO.puts("starting postgres instance...")

    args = ["-D", "postgres/data", "-l", "logfile", "start"]
    case :os.type() do
      {:win32, _} ->
        spawn(fn -> System.cmd("pg_ctl", args, into: stdout) end)
      {:unix, _} ->
 System.cmd( ...