Assert_broadcast does not see intercepted payload?

I got interception going on my channel:
intercept [“joined”, “left”]

def handle_out("joined", payload, socket) do
  this_profile = socket.assigns[:profile]
  that_profile = Dict.get(payload, "profile")
  unless == that_profile["id"] do
    npayload = Map.put(payload, :connection, 123)
    push socket, "joined", npayload
  {:noreply, socket}


when I run a test to verify my payload:

assert_broadcast "joined", msg, @default_assert_timeout Logger.debug "msg: #{inspect msg, pretty: true}"

the Logger output:

2016-07-22 09:16:42.830 [debug] msg: %{profile: %{“picture_url” => “”, “zip” => nil}}

no connection field. Is assert_broadcast supposed to see message modified by the interceptor?

Try assert_push. I think assert_broadcast is to test that a broadcast went out, without checking one channel specifically.