Add coverage tests for LeaderElection foreign-pid registration path

test/aprsme/cluster/leader_election_test.exs

@@ -492,6 +492,34 @@ defmodule Aprsme.Cluster.LeaderElectionTest do
     end
   end
 
+  describe "handle_info(:attempt_election) with another pid holding the global key" do
+    test "becomes non-leader when another process holds the registration (:no path)" do
+      # Pre-register a different pid (not the test process) so attempt_election
+      # sees a foreign pid and returns :no via check_own_registration.
+      other = spawn(fn -> Process.sleep(:infinity) end)
+      :global.unregister_name(@election_key)
+      :global.register_name(@election_key, other)
+
+      try do
+        state = %LeaderElection{
+          cluster_enabled: false,
+          is_leader: false,
+          leader_node: nil
+        }
+
+        assert {:noreply, new_state} =
+                 LeaderElection.handle_info(:attempt_election, state)
+
+        # We got the :no path. leader_node should be the foreign pid's node.
+        assert new_state.is_leader == false
+        assert new_state.leader_node == node(other)
+      after
+        Process.exit(other, :kill)
+        :global.unregister_name(@election_key)
+      end
+    end
+  end
+
   describe "init/1 in clustered mode (schedule_initial_election(true) path)" do
     test "schedules :check_cluster_and_elect and :force_election_timeout" do
       # Capture the test process — init/1 runs in this process and sends