Socket disconnected when using `live_isolated/3`

I have a nested LiveView in which different kinds of children views can come and go dynamically. I want to unit-test these children views individually without setting up the more complicated parent.

My thought was to setup a dummy LiveView that renders the component to be tested. Then I want to use live_isolated/3 to trigger the test.

Something like that.

defmodule MyDummyLiveView do
  use MyAppWeb, :live_view

  # imports aliases and stuff

  def mount(_params, _session, socket) do
    %{my_params: my_params} = get_connect_params(socket)
    {:ok, assign(socket, %{params: my_params})}

  def render(%{params: my_params}) do
    live_component(MySubComponent, params: my_params)

Then the unit test would look like

test "some test", %{conn: conn} do
  my_params = %{foo: 1, bar: 2}

  {:ok, view, _html} =
    |> put_connect_params(%{my_params: my_params})
    |> live_isolated(MyDummyLiveView)

   html = view
   |> element("#some_element")
   |> render_click()

   # assertion on html

This doesn’t work because the socket in the mount/3 function seems to be disconnected. get_connectparam/1 returns nil.

How would I make sure that mount/3 gets a connected socket?