This server is initiated upon application launch when operating in the test environment. This is done to allow tests to start their own custom servers and schedule custom systems.

A basic test system setup may look like this:

  defmodule Demo.Systems.MoveHeroTest do
    use ExUnit.Case

    defmodule DemoTest do
      @moduledoc "A setup that does not schedule any system"
      use Ecspanse

      @impl true
      def setup(data) do
        data
      end
    end

    setup do
      {:ok, _pid} = start_supervised({DemoTest, :test})
      Ecspanse.System.debug()
    end
  end

In the test setup block, the server is started with the tuple {DemoTest, :test}. This is needed to point Ecspanse to start the Ecspanse.Server with the DemoTest setup.

The Ecspanse.System.debug/0 call grants the test pid Ecspanse.System powers. Meaning that it can runt commands without being in the context of a system.