elixir - How to stub (or prevent running) of a call to a worker in my ExUnit test? -

i have phoenix app (which restful api no front end) , 1 of controllers stuff want test, @ end of controller calls dispatcher sends payload off worker (run under poolboy) process received payload in background.

in controller test, don't want test stuff worker doing, want know dispatcher worker has been called correct payload (e.g. calledwith() )

and ideally dispatcher function stubbed, actual thing never ran.

i pass additional parameter dispatcher ensure never runs code on worker, seems messy, whereas stub seems idea.

thanks

edit

dispatcher code:

defmodule convert.dispatcher   def dispatch(data) fo    spawn (fn() -> parallel(data) end)   end    def parallel(data)     #pass off poolboy   end end 

test mock:

with_mock convert.dispatcher, [dispatch: fn(_opts) -> :ok end]   response = conn(:post, "/", data) |> send_request   body = response.resp_body |> poison.decode!   assert response.status == 201   assert called convert.dispatcher.dispatch("") end 

there mocking library called "mock" can use temporarily mock modules in tests. example:

defmodule mycontrollertest   use exunit.case, async: false   use routerhelper   import mock    setup     logger.disable(self())     :ok   end    test "dispatches worker"     with_mock mydispatcher, [dispatch: fn(_opts) -> :ok end]       call(router, :get, "/my/route")       assert called mydispatcher.dispatch(foo: "bar")     end   end end