conn_case.ex

defmodule Dd.Web.ConnCase do
  use ExUnit.CaseTemplate

  using do
    quote do
      use Phoenix.ConnTest
      import Dd.Web.Router.Helpers
      import Dd.Web.TestHelpers # Helpers added directly to ConnCase

      @endpoint Dd.Web.Endpoint
    end
  end


  setup tags do
    :ok = Ecto.Adapters.SQL.Sandbox.checkout(Dd.Repo)
    unless tags[:async] do
      Ecto.Adapters.SQL.Sandbox.mode(Dd.Repo, {:shared, self()})
    end
    {:ok, conn: Phoenix.ConnTest.build_conn()}
  end

end

test_helpers.ex

defmodule Dd.Web.TestHelpers do
  use Phoenix.ConnTest

  def json_api_conn do
    build_conn()
    |> put_req_header("accept", "application/vnd.api+json")
    |> put_req_header("content-type", "application/vnd.api+json")
  end

  def json_api_conn(user) do
    conn = Guardian.Plug.api_sign_in(build_conn(), user)
    token = Guardian.Plug.current_token(conn)

    json_api_conn()
    |> put_req_header("authorization", "Bearer " <> token)
  end
end