Get Flash after `render_submit` in LiveView test

In the Phoenix.LiveViewTest module, we can get the structured Flash after certain actions like assert_redirected:

flash = assert_redirect(view, ~p"/user/search")
assert_single_flash(flash, "This user was deleted", type: :warning)

We use the Flashy library for more fancy flashes in our code, so this home-made assert_single_flash helper can assert on many things like the type of flash, whether or not it is closable, etc.

I’d like to get this same structured flash response after render_submit, but it does not seem possible to do:

html =
  view
  |> element("#name-modal form")
  |> render_submit(%{"first_name" => "NewName"})

assert html =~ "Success."

All I seem to be able to do is assert on the returned HTML, which should contain the flash message. This does not allow for fine-grained assertions though.

Is there a way to get the current flash after the render_submit has completed?