refactor: apply review comments

test/mv_web/live/group_live/show_test.exs

@@ -219,8 +219,8 @@ defmodule MvWeb.GroupLive.ShowTest do
     end
   end
 
-  @moduletag :slow
   describe "performance" do
+    @describetag :slow
     test "member list is loaded efficiently (no N+1 queries)", %{conn: conn} do
       group = Fixtures.group_fixture()
 
@@ -236,12 +236,31 @@ defmodule MvWeb.GroupLive.ShowTest do
         )
       end)
 
+      # Count queries using Telemetry
+      query_count_agent = Agent.start_link(fn -> 0 end) |> elem(1)
+
+      handler = fn _event, _measurements, _metadata, _config ->
+        Agent.update(query_count_agent, &(&1 + 1))
+      end
+
+      handler_id = "test-query-counter-#{System.unique_integer([:positive])}"
+      :telemetry.attach(handler_id, [:ash, :query, :start], handler, nil)
+
       {:ok, _view, html} = live(conn, "/groups/#{group.slug}")
 
+      final_count = Agent.get(query_count_agent, & &1)
+      :telemetry.detach(handler_id)
+
       # All members should be displayed
       Enum.each(members, fn member ->
         assert html =~ member.first_name or html =~ member.last_name
       end)
+
+      # Verify query count is reasonable (should avoid N+1 queries)
+      # Expected: 1 query for group lookup + 1 query for members (with preload)
+      # Allow some overhead for LiveView setup queries
+      assert final_count <= 5,
+             "Expected max 5 queries (group + members preload + LiveView setup), got #{final_count}. This suggests N+1 query problem."
     end
 
     test "slug lookup is efficient (uses unique_slug index)", %{conn: conn} do