diff --git a/notification_test.go b/notification_test.go
index 740dec9..414ebff 100644
--- a/notification_test.go
+++ b/notification_test.go
@@ -39,17 +39,17 @@ func TestGetNotifications(t *testing.T) {
 	if len(ns) != 2 {
 		t.Fatalf("result should be two: %d", len(ns))
 	}
-	if ns[0].ID != 122 {
+	if ns[0].ID != "122" {
 		t.Fatalf("want %v but %v", 122, ns[0].ID)
 	}
-	if ns[1].ID != 123 {
+	if ns[1].ID != "123" {
 		t.Fatalf("want %v but %v", 123, ns[1].ID)
 	}
 	n, err := client.GetNotification(context.Background(), 123)
 	if err != nil {
 		t.Fatalf("should not be fail: %v", err)
 	}
-	if n.ID != 123 {
+	if n.ID != "123" {
 		t.Fatalf("want %v but %v", 123, n.ID)
 	}
 	err = client.ClearNotifications(context.Background())
diff --git a/streaming_ws_test.go b/streaming_ws_test.go
index f52477c..3c8974b 100644
--- a/streaming_ws_test.go
+++ b/streaming_ws_test.go
@@ -117,7 +117,7 @@ func wsTest(t *testing.T, q chan Event, cancel func()) {
 	if events[0].(*UpdateEvent).Status.Content != "foo" {
 		t.Fatalf("want %q but %q", "foo", events[0].(*UpdateEvent).Status.Content)
 	}
-	if events[1].(*NotificationEvent).Notification.ID != 123 {
+	if events[1].(*NotificationEvent).Notification.ID != "123" {
 		t.Fatalf("want %d but %d", 123, events[1].(*NotificationEvent).Notification.ID)
 	}
 	if events[2].(*DeleteEvent).ID != 1234567 {