servertest: close server state during cleanup

Release the NodeStore and database after clients and background workers stop.

hscontrol/servertest/lifecycle_test.go

@@ -660,3 +660,13 @@ func describeNetmap(c *servertest.TestClient) string {
 
 	return out.String()
 }
+
+func TestServerStateCleanup(t *testing.T) {
+	var srv *servertest.TestServer
+
+	t.Run("server", func(t *testing.T) { srv = servertest.NewServer(t) })
+
+	database, err := srv.State().DB().DB.DB()
+	require.NoError(t, err)
+	require.ErrorContains(t, database.Ping(), "database is closed")
+}

hscontrol/servertest/server.go

@@ -203,6 +203,14 @@ func NewServer(tb testing.TB, opts ...ServerOption) *TestServer {
 		tb.Fatalf("servertest: NewHeadscale: %v", err)
 	}
 
+	// Registered first so clients, HTTP, and background subsystems stop first.
+	tb.Cleanup(func() {
+		err := app.GetState().Close()
+		if err != nil {
+			tb.Errorf("servertest: close state: %v", err)
+		}
+	})
+
 	// Set a minimal DERP map so MapResponse generation works.
 	app.GetState().SetDERPMap(&tailcfg.DERPMap{
 		Regions: map[tailcfg.DERPRegionID]*tailcfg.DERPRegion{