layer1: add namespace subscriber adapter step 19

pkg/utils/namespace_manager_test.go

@@ -265,3 +265,35 @@ func TestNamespaceManagerDispatchResyncFailure(t *testing.T) {
 		t.Fatalf("expected subscriber error to be stored")
 	}
 }
+
+func TestNamespaceSubscriberFuncs(t *testing.T) {
+	addCalls := 0
+	removeCalls := 0
+	resyncCalls := 0
+	subscriber := NamespaceSubscriberFuncs{
+		SubscriberName: "router",
+		AddFunc: func(ctx context.Context, record NamespaceRecord) error {
+			addCalls++
+			return nil
+		},
+		RemoveFunc: func(ctx context.Context, record NamespaceRecord) error {
+			removeCalls++
+			return nil
+		},
+		ResyncFunc: func(ctx context.Context, record NamespaceRecord) error {
+			resyncCalls++
+			return nil
+		},
+	}
+
+	if subscriber.Name() != "router" {
+		t.Fatalf("expected subscriber name router")
+	}
+	_ = subscriber.OnNamespaceAdd(context.Background(), NamespaceRecord{Name: "tenant-a"})
+	_ = subscriber.OnNamespaceRemove(context.Background(), NamespaceRecord{Name: "tenant-a"})
+	_ = subscriber.OnNamespaceResync(context.Background(), NamespaceRecord{Name: "tenant-a"})
+
+	if addCalls != 1 || removeCalls != 1 || resyncCalls != 1 {
+		t.Fatalf("expected all functional callbacks to run once")
+	}
+}