fix

src/pages/Testen.jsx

@@ -98,6 +98,9 @@ const Testen = () => {
     setError(null);
     try {
       const q = await generateWeeklyQuiz(currentUser.id, weekNumber);
+      if (!q?.questions?.length) {
+        throw new Error('No questions could be generated for this week. Please try again.');
+      }
       setQuiz(q);
       setCurrentQ(0);
       setAnswers({});
@@ -323,6 +326,17 @@ const Testen = () => {
   // ─── Active Quiz ──────────────────────────────────────────
   if (phase === 'quiz' && quiz) {
     const q = quiz.questions[currentQ];
+
+    // Safety guard — should never happen, but prevents a crash if questions array is empty
+    if (!q) {
+      return (
+        <div className="p-4 md:p-8 max-w-2xl mx-auto text-center py-20">
+          <p className="text-red-500 font-medium">Something went wrong loading this question.</p>
+          <Button className="mt-4" onClick={() => setPhase('intro')}>Back</Button>
+        </div>
+      );
+    }
+
     const selectedAnswer = answers[q.id];
     const isCorrect = selectedAnswer === q.correctIndex;
     const progress = ((currentQ + (showFeedback ? 1 : 0)) / quiz.questions.length) * 100;