fix: close expired test attempts at the attempt limit

classes/service.go

@@ -286,6 +286,9 @@ func (s *Service) Start(ctx context.Context, userID uint, slug, category string)
 
 func (s *Service) startTest(ctx context.Context, userID uint, quiz *models.Quiz) (*Started, error) {
 	var st *Started
+	// limited refuses the start after the commit, so the expired attempts
+	// closed on the way stay closed (an error would roll the closes back).
+	var limited bool
 	err := lagoon.Transaction(ctx, s.DB, func(ctx context.Context, tx *gorm.DB) error {
 		tx = tx.WithContext(ctx)
 		if err := tx.Exec(`SELECT pg_advisory_xact_lock(hashtext(?))`, AttemptLockKey(quiz.ID, userID)).Error; err != nil {
@@ -327,7 +330,8 @@ func (s *Service) startTest(ctx context.Context, userID uint, quiz *models.Quiz)
 			return nil
 		}
 		if left := AttemptsLeft(quiz, int(used)); left != nil && *left == 0 {
-			return ErrAttemptLimit
+			limited = true
+			return nil
 		}
 		attempt := &models.Attempt{QuizID: quiz.ID, UserID: userID, StartedAt: now.UTC()}
 		maxPoints, err := s.maxPoints(ctx, tx, attempt)
@@ -344,6 +348,9 @@ func (s *Service) startTest(ctx context.Context, userID uint, quiz *models.Quiz)
 	if err != nil {
 		return nil, err
 	}
+	if limited {
+		return nil, ErrAttemptLimit
+	}
 	return st, nil
 }
 

test_mode_postgres_test.go

@@ -286,6 +286,38 @@ VALUES ('Stary', 'stary', true, 50, false, NOW(), NOW())`).Error)
 		}
 	})
 
+	t.Run("the last expired attempt is closed at the limit", func(t *testing.T) {
+		f := seedQuiz(t, gdb, "test-wygasly-limit", test(func(q *models.Quiz) {
+			q.TimeLimitSeconds = intPtr(60)
+			q.MaxAttempts = intPtr(1)
+		}))
+		u, _ := newUser(t, gdb, "lazy-limit@example.com")
+		t0 := time.Now().UTC().Truncate(time.Second)
+		clock := t0
+		svc := &classes.Service{DB: gdb, Now: func() time.Time { return clock }, Grace: 5 * time.Second}
+		st, err := svc.Start(t.Context(), u.ID, "test-wygasly-limit", "")
+		must(t, err)
+		clock = t0.Add(10 * time.Second)
+		_, err = svc.Answer(t.Context(), u.ID, st.Attempt.ID, classes.AnswerInput{QuestionID: f.single.ID, AnswerIDs: []uint{f.singleRight.ID}})
+		must(t, err)
+
+		clock = t0.Add(70 * time.Second)
+		if _, err := svc.Start(t.Context(), u.ID, "test-wygasly-limit", ""); !errors.Is(err, classes.ErrAttemptLimit) {
+			t.Errorf("start after the last attempt expired = %v, want ErrAttemptLimit", err)
+		}
+		var old models.Attempt
+		must(t, gdb.Take(&old, st.Attempt.ID).Error)
+		if old.CompletedAt == nil || !old.CompletedAt.Equal(t0.Add(60*time.Second)) {
+			t.Errorf("expired attempt completed_at = %v, want %v (closed despite the limit)", old.CompletedAt, t0.Add(60*time.Second))
+		}
+		if old.ScorePoints != 1 || old.MaxPoints != 4 {
+			t.Errorf("expired attempt score = %v / %d, want 1 / 4", old.ScorePoints, old.MaxPoints)
+		}
+		if n := countAttempts(t, f.quiz.ID, u.ID); n != 1 {
+			t.Errorf("attempts after the refused start = %d, want 1", n)
+		}
+	})
+
 	t.Run("a shuffled test keeps its order", func(t *testing.T) {
 		c := &client{t: t, h: h}
 		seedQuiz(t, gdb, "test-losowy", test(func(q *models.Quiz) { q.ShuffleQuestions = true }))