Dont background thread so we dont break tests

changedetectionio/blueprint/ui/__init__.py

@@ -194,9 +194,9 @@ def construct_blueprint(datastore: ChangeDetectionStore, update_q, worker_pool,
         tag_limit = request.args.get('tag')
         now = int(time.time())
 
-        # Mark watches as viewed in background thread to avoid blocking
-        def mark_viewed_background():
-            """Background thread to mark watches as viewed - discarded after completion."""
+        # Mark watches as viewed - use background thread only for large watch counts
+        def mark_viewed_impl():
+            """Mark watches as viewed - can run synchronously or in background thread."""
             marked_count = 0
             try:
                 for watch_uuid, watch in datastore.data['watching'].items():
@@ -209,15 +209,23 @@ def construct_blueprint(datastore: ChangeDetectionStore, update_q, worker_pool,
                     datastore.set_last_viewed(watch_uuid, now)
                     marked_count += 1
 
-                logger.info(f"Background marking complete: {marked_count} watches marked as viewed")
+                logger.info(f"Marking complete: {marked_count} watches marked as viewed")
             except Exception as e:
-                logger.error(f"Error in background mark as viewed: {e}")
+                logger.error(f"Error marking as viewed: {e}")
 
-        # Start background thread and return immediately
-        thread = threading.Thread(target=mark_viewed_background, daemon=True)
-        thread.start()
+        # For small watch counts (< 10), run synchronously to avoid race conditions in tests
+        # For larger counts, use background thread to avoid blocking the UI
+        watch_count = len(datastore.data['watching'])
+        if watch_count < 10:
+            # Run synchronously for small watch counts
+            mark_viewed_impl()
+            flash(gettext("Marked as viewed."))
+        else:
+            # Start background thread for large watch counts
+            thread = threading.Thread(target=mark_viewed_impl, daemon=True)
+            thread.start()
+            flash(gettext("Marking watches as viewed in background..."))
 
-        flash(gettext("Marking watches as viewed in background..."))
         return redirect(url_for('watchlist.index', tag=tag_limit))
 
     @ui_blueprint.route("/delete", methods=['GET'])