Use child router in the test cases

I have two routers in my app. I am forwarding api calls which start with /admin_api/v1 to a child router from the main router.

                       forward "/admin_api/v1", Admin.ApiWeb.Router

It works fine when I test it with Postman. Both routers are working as expected. This is path in the child router.

            qa_question_path  DELETE  /qa_questions/:nuton_id              NutonAdminApi.QaQuestionController :delete
            qa_question_path  PUT     /qa_questions/:nuton_id              NutonAdminApi.QaQuestionController :update

This is route in the parent route for the same entity.

      qa_question_path  GET   /api/v1/qa_questions                 NutonApi.QaQuestionController :index
      qa_question_path  POST  /api/v1/qa_questions                 NutonApi.QaQuestionController :create

Their path names are the same but their EP are different.
When I run following test case

 json_resp =
    qa_question_path(conn, :update, id),
  |> json_response(200)

It gives me this error:

   ** (ArgumentError) no action :update for ApiWeb.Router.Helpers.qa_question_path/3. The following actions/clauses are supported:
     qa_question_path(conn_or_endpoint, :create, params \\ [])
     qa_question_path(conn_or_endpoint, :index, params \\ [])
     qa_question_path(conn_or_endpoint, :show, nuton_id, params \\ [])

I understand the issue because of the same path names in both routes . It just checks if the path exist in the parent and raise an error, but how can I include child router in the test cases so that it will check if the path exist in it.