test.ex

defmodule Test.Sup do
  use Supervisor

  def start_link(opts), do: Supervisor.start_link(__MODULE__, opts, name: __MODULE__)

  def init([]) do
    children = [
      # Supervisor.Spec.worker(Test.Server, [[]]),
      Test.Server
    ]

    supervise(children, strategy: :one_for_one)
  end
end


defmodule Test.Server do
  use GenServer
  
  def start_link(opts), do: GenServer.start_link(__MODULE__, opts, name: __MODULE__)

  def init([]) do
    {:ok, :no_state}
  end
end