hcs.SyncServices(nil)
	if len(hcs.services) != 0 {
		t.Errorf("expected 0 services, got %d", len(hcs.services))
	}

	// sync multiple services
	nsn1 := mknsn("a", "b")
	nsn2 := mknsn("c", "d")
	nsn3 := mknsn("e", "f")
	nsn4 := mknsn("g", "h")
	hcs.SyncServices(map[types.NamespacedName]uint16{
		nsn1: 9376,
		nsn2: 12909,
		nsn3: 11113,
	})
	if len(hcs.services) != 3 {