Property-Based Testing with PropEr in Elixir/

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Parallel Tests

Parallel Tests

Take a look at the parallel testing of the application.

We'll cover the following...

As with the last chapter, the parallel version of our system can be adapted by just declaring a new property and reusing the same model, to see if any glaring concurrency issues can be found.

Let’s take a look at the below code and watch the property in action.

Code

The property "parallel stateful property" has been highlighted in the following code.

defmodule Bookstore.MixProject do
  use Mix.Project

  def project do
    [
      app: :bookstore,
      version: "0.1.0",
      elixir: "~> 1.6",
      elixirc_paths: elixirc_paths(Mix.env),
      start_permanent: Mix.env() == :prod,
      deps: deps(),
      escript: escript_config()
    ]
  end

  defp elixirc_paths(:test), do: ["lib","test/"]
  defp elixirc_paths(_), do: ["lib"]

  # Run "mix help compile.app" to learn about applications.
  def application do
    [
      extra_applications: [:logger],
      mod: {Bookstore.App, []},
      env: [
        pg: [
          # Single quotes are important
          user: 'postgres', # replace with your own $USER
          password: '',
          database: 'bookstore_db', # as specified by bookstore_init.ex
          host: '127.0.0.1',
          port: 5432,
          ssl: false # not for tests!
        ]
      ]
    ]
  end

  # Run "mix help deps" to learn about dependencies.
  defp deps do
    [
      {:eql, "~> 0.1.2", manager: :rebar3},
      {:pgsql, "~> 26.0"},
      {:propcheck, "~> 1.1", only: [:test, :dev]}
    ]
  end

  defp escript_config do
    [main_module: Bookstore.Init, app: nil]
  end
end
Parallel testing

Once again, there are few changes ...