Background

I have a project where I have separated my tests into two categories: Unit tests and Integration tests.

My objective is to have 3 commands that do the following:

• mix test.unit: executes all unit tests
• mix test.integration: executes all integration tests
• mix test: executes mix test.unit and then mix test.integration

I can somewhat replicate my first objective, instead of mix test.unit I am using environment variables and I am running MIX_ENV=unit mix test.

Problem

There are however a few problems with this approach:

• It is way more verbose than the intended command
• The only way I know of taking advantage of this is by littering my mix.exs with environment variables and pattern matching function that do something depending on the environment
• It is very easy to miss the environment variable name only to see things blow up
• I dont get help not auto complete if I type mix help

Research

I thought about using a mix alias like in this post:

But not only am I unsure on how to do it, I don’t even think I can change the default behavior of mix test to run both unit and integration tests separately.

Code

Thus far, all I have no is a half-broken mix.exs file that works:

defmodule MarketManager.MixProject do
  use Mix.Project

  @test_envs [:unit, :integration]

  ##########
  # Public #
  ##########

  def project do
    [
      app: :market_manager,
      version: "0.1.0",
      elixir: "~> 1.9",
      start_permanent: Mix.env() == :prod,
      deps: deps(),
      elixirc_paths: elixirc_paths(Mix.env),
      test_paths: test_paths(Mix.env)
    ]
  end

  # Run "mix help compile.app" to learn about applications.
  def application do
    [
      extra_applications: applications(Mix.env),
      mod: {MarketManager.Application, [env: Mix.env]}
    ]
  end

  ###########
  # Private #
  ###########

  defp applications(:integration), do: applications(:default) ++ [:cowboy, :plug]
  defp applications(_),     do: [:logger]

  # Run "mix help deps" to learn about dependencies.
  defp deps do
    [
      {:httpoison, "~> 1.6"},
      {:jason, "~> 1.2"},

      # Testing and Dev
      {:hammox, "~> 0.2", only: @test_envs},
      {:mix_test_watch, "~> 1.0", only: @test_envs, runtime: false},
      {:plug_cowboy, "~> 2.0", only: @test_envs}
    ]
  end

  defp elixirc_paths(env) when env in @test_envs, do: ["test/support", "lib"]
  defp elixirc_paths(_),     do: ["lib"]

  defp test_paths(:integration), do: ["test/integration"]
  defp test_paths(:unit), do: ["test/unit"]
  defp test_paths(_), do: ["test/unit"]

end

Which was inspired in the blog:

Questions

As you can probably tell from reading my mix.exs file, it is a half broken mess where, in order to compile, I have to mix the definitions of MIX_ENV=unit mix test and mix test (check the test_paths) functions.

This brings all sorts of pain when developing.

How can I fix this file, so it has the desired behavior?