Cannot find mock/stub in process #PID<0.512.0> using Req

[ijunaidfarooq]

I have a simple GenServer making an HTTP request

defmodule GamePlay do
  use GenServer

  alias Wrapper

  def start_link(_args) do
    GenServer.start_link(__MODULE__, %{}, name: __MODULE__)
  end

  def init(state) do
    {:ok, state, {:continue, :put_mapping}}
  end

  def handle_continue(:put_mapping, state) do
    mapping = %{
      "index_patterns" => ["game_play-*"]
    }

    config = Application.get_env(:search_flask, :elasticsearch_seeds, [])

    if Keyword.get(config, :enabled?, true) do
      Wrapper.create_template_mappings("game_play", mapping)
    end

    {:noreply, state}
  end
end

and I am trying to put to test using Req, in Wrapper, I am sending an HTTP request using Req. but it only works once when I delete _build/test folder after that it stops working

defmodule GamePlayTest do
  use ExUnit.Case, async: true

  alias GamePlay
  alias Wrapper

  describe "GamePlay" do
    setup do
      on_exit(fn ->
        Req.Test.verify_on_exit!()
      end)

      :ok
    end

    test "sends the correct request to Elasticsearch" do
      Req.Test.stub(Wrapper, fn conn ->
        Req.Test.json(
          conn,
          %{"acknowledged" => true}
        )
      end)

      assert {:ok, pid} = GamePlay.start_link(%{})

      assert %Req.Response{body: %{"acknowledged" => true}, status: 200} =
               Req.get!(Application.get_env(:search_flask, :elasticsearch_req_options, []))
    end
  end
end

I have this in test.exs as well.

config :search_flask,
  elasticsearch_req_options: [
    plug: {Req.Test, Wrapper}
  ]

the is the error.

     ** (EXIT from #PID<0.570.0>) an exception was raised:
         ** (RuntimeError) cannot find mock/stub Wrapper in process #PID<0.571.0>
             (req 0.5.6) lib/req/test.ex:399: Req.Test.__fetch_plug__/1
             (req 0.5.6) lib/req/test.ex:632: Req.Test.call/2
             (req 0.5.6) lib/req/steps.ex:927: Req.Steps.run_plug/1
             (req 0.5.6) lib/req/request.ex:1103: Req.Request.run_request/1
             (req 0.5.6) lib/req/request.ex:1047: Req.Request.run/1
             (search_flask 1.3.0) lib/game_play.ex:47: GamePlay.handle_continue/2
             (stdlib 6.0) gen_server.erl:2163: :gen_server.try_handle_continue/3
             (stdlib 6.0) gen_server.erl:2072: :gen_server.loop/7
             (stdlib 6.0) proc_lib.erl:329: :proc_lib.init_p_do_apply/3

the test is simple as well but it only reaches to Wrapper.create_template_mappings only once after that it just keep failing.

[al2o3cr]

The issue is that you’re setting the stub in the test process, but then attempting to use the stub in the GamePlay process.

Using an explicit allowance should help - the second example for Req.Test is nearly identical to your setup.

[ijunaidfarooq]

Thank you. one last thing though when I add this geneserver to application.ex in children, this error rises again but without being in children list this works fine.

Should I just exclude them from children when running in test mode?

[tubedude]

@ijunaidfarooq I came up to a similar issue and solved like this:

HWY Tackle: Deep Req.Test.allow/3 or adding Test-Specific Code in Production Function

Hi everyone, I’m working on a GenServer module to handle incoming messages in my Elixir application. I’m looking for feedback on how I’m currently handling test-specific code within a production function. Below, I’ve provided the relevant parts of the code for context. In my test, I create a Req.Test.Stub, but the actual Req.request occurs in a Task that is spawned within the GenServer. I attempted to bubble up the pid from the Task in the test, but this caused the function execution to occur…

Check that out and see if it helps. It is working. But I still don’t know if that is the best solution.

[ijunaidfarooq]

Thank you.