I’m running into an edge case with phoenix testing. I’ve got an on_mount handler behaving like a plug which creates a db session for a given client:

defmodule SgWeb.InitSessionId do
  @moduledoc """
  Adds the DB session ID to the assigns
  """
  import Phoenix.Component
  alias Sg.Sessions

  def on_mount(:default, _params, %{"client_id" => client_id}, socket) do
    session =
      case Sessions.get_session_by_client_id(client_id) do
        nil ->
          {:ok, session} = Sessions.create_session(%{client_id: client_id})
          session

        existing_session ->
          existing_session
      end

    {:cont, assign(socket, session_id: session.id)}
  end
end

However, whenever I try to test this as one would a plug, the assign function blows up and tells me I need to use render_component. I understand the logic, generally, but there has to be a way around this - I’m literally following a use case described in the docs in this instance (Phoenix.LiveView — Phoenix LiveView v0.19.5). Is there an easy way to mock a socket/assigns without triggering the exceptions?