fix

src/lib/testService.js

@@ -94,11 +94,15 @@ async function selectTestTopics(userId, isoWeekNumber) {
     const weekContent = await getCurrentWeekContent(isoWeekNumber);
 
     if (weekContent && weekContent.topics && weekContent.topics.length > 0) {
-      const primaryTopic = weekContent.topics[0]; // Use first topic as primary for now
+      const primaryTopic = weekContent.topics[0];
+      if (!primaryTopic?.id) {
+        console.warn('[Test] First curriculum topic has no id — falling back to hash');
+      } else {
         const others = topics.filter(t => t.id !== primaryTopic.id);
         const reviewTopics = sample(others, Math.min(5, others.length));
         return { primaryTopic, reviewTopics, isReviewWeek: false };
       }
+    }
   } catch (e) {
     console.warn('[Test] Curriculum lookup failed, falling back to hash:', e.message);
   }