How to test an infinite, recursive Task in Elixir

Question

Please check this code:

defmodule InfinitePollTask do
  def poll(opts \\ [])
    # function body code here
    poll(new_opts)
  end
end

I want to write a unit test for the function body code, assuming the function body perform some important computation using opts and produce a new_opts for the next iteration.

Answer 1

I'd just pull the computation out into a separate function that returns new_opts, and test that:

defmodule InfinitePollTask do
  def poll(opts \\ [])
    poll(do_poll(opts))
  end

  def do_poll(opts)
    # important computation
  end
end

defmodule InfinitePollTaskTest do
  use ExUnit.Case

  test "some case" do
    assert InfinitePollTask.do_poll(some_opts) == some_result_opts
  end
end