diff --git a/test/aprsme_web/live/map_live/display_manager_test.exs b/test/aprsme_web/live/map_live/display_manager_test.exs
index 90446a4..2911245 100644
--- a/test/aprsme_web/live/map_live/display_manager_test.exs
+++ b/test/aprsme_web/live/map_live/display_manager_test.exs
@@ -7,6 +7,7 @@ defmodule AprsmeWeb.MapLive.DisplayManagerTest do
   setup do
     socket = %Socket{
       assigns: %{
+        __changed__: %{},
         visible_packets: %{},
         tracked_callsign: nil,
         packet_age_threshold: nil,
@@ -43,6 +44,7 @@ defmodule AprsmeWeb.MapLive.DisplayManagerTest do
   # Builds from known base defaults so callers can pass only overrides.
   defp update_assigns(socket, overrides) do
     base = %{
+      __changed__: %{},
       visible_packets: %{},
       tracked_callsign: nil,
       packet_age_threshold: nil,