fix: Wait for remote update goroutine to finshes

Wait until the goroutine repsonsible for updates from the remote
finishes to ensure that all references to the database are proplery
releases.

This was causing test cleanup on windows to fail since the go-routine
was still active when the test had finished executing.

internal/backend/user.go

@@ -24,6 +24,9 @@ type user struct {
 	states      map[int]*State
 	statesLock  sync.RWMutex
 	nextStateID int
+
+	updateStopCh chan struct{}
+	updateWG     sync.WaitGroup
 }
 
 func newUser(ctx context.Context, userID string, client *ent.Client, remote *remote.User, store store.Store, delimiter string) (*user, error) {
@@ -32,27 +35,35 @@ func newUser(ctx context.Context, userID string, client *ent.Client, remote *rem
 	}
 
 	user := &user{
-		userID:    userID,
-		remote:    remote,
-		store:     store,
-		delimiter: delimiter,
-		client:    client,
-		states:    make(map[int]*State),
+		userID:       userID,
+		remote:       remote,
+		store:        store,
+		delimiter:    delimiter,
+		client:       client,
+		states:       make(map[int]*State),
+		updateStopCh: make(chan struct{}),
 	}
 
 	if err := user.deleteAllMessagesMarkedDeleted(ctx); err != nil {
 		return nil, err
 	}
 
+	user.updateWG.Add(1)
+
 	go func() {
-		for update := range remote.GetUpdates() {
-			update := update
-
-			if err := user.tx(context.Background(), func(tx *ent.Tx) error {
-				defer update.Done()
-				return user.apply(context.Background(), tx, update)
-			}); err != nil {
-				logrus.WithError(err).Error("Failed to apply update")
+		defer user.updateWG.Done()
+
+		for {
+			select {
+			case update := <-remote.GetUpdates():
+				if err := user.tx(context.Background(), func(tx *ent.Tx) error {
+					defer update.Done()
+					return user.apply(context.Background(), tx, update)
+				}); err != nil {
+					logrus.WithError(err).Errorf("Failed to apply update: %v", update)
+				}
+			case <-user.updateStopCh:
+				return
 			}
 		}
 	}()
@@ -99,6 +110,10 @@ func (user *user) tx(ctx context.Context, fn func(tx *ent.Tx) error) error {
 func (user *user) close(ctx context.Context) error {
 	user.closeStates()
 
+	// Wait until the connector update go routine has finished.
+	close(user.updateStopCh)
+	user.updateWG.Wait()
+
 	if err := user.remote.CloseAndSerializeOperationQueue(); err != nil {
 		return fmt.Errorf("failed to close user remote: %w", err)
 	}