fix: return 0 if there is no job with the given state

queue.go

@@ -303,12 +303,12 @@ func (q *SQLiteQueue) Count(ctx context.Context) (*JobCount, error) {
 	row := q.readDB.QueryRowContext(
 		ctx,
 		`SELECT COUNT(rowid) AS total,
-    SUM(CASE WHEN state = ? THEN 1 ELSE 0 END) as pending,
-    SUM(CASE WHEN state = ? THEN 1 ELSE 0 END) as running,
-    SUM(CASE WHEN state = ? THEN 1 ELSE 0 END) as retry,
-    SUM(CASE WHEN state = ? THEN 1 ELSE 0 END) as failed,
-    SUM(CASE WHEN state = ? THEN 1 ELSE 0 END) as completed
-    from queuelite_job`,
+    	COALESCE(SUM(CASE WHEN state = ? THEN 1 ELSE 0 END), 0) as pending,
+    	COALESCE(SUM(CASE WHEN state = ? THEN 1 ELSE 0 END), 0) as running,
+    	COALESCE(SUM(CASE WHEN state = ? THEN 1 ELSE 0 END), 0) as retry,
+    	COALESCE(SUM(CASE WHEN state = ? THEN 1 ELSE 0 END), 0) as failed,
+    	COALESCE(SUM(CASE WHEN state = ? THEN 1 ELSE 0 END), 0) as completed
+    	from queuelite_job`,
 		JobStatePending,
 		JobStateRunning,
 		JobStateRetry,
@@ -325,6 +325,9 @@ func (q *SQLiteQueue) Count(ctx context.Context) (*JobCount, error) {
 		&count.Failed,
 		&count.Completed,
 	); err != nil {
+		if errors.Is(err, sql.ErrNoRows) {
+			return &JobCount{}, nil
+		}
 		return nil, err
 	}
 

queue_test.go

@@ -91,6 +91,8 @@ func TestIsEmpty(t *testing.T) {
 	})
 
 	t.Run("should return false if the queue is not empty", func(tt *testing.T) {
+		os.Remove(dbDir)
+
 		queue, err := queuelite.NewSQLiteQueue(dbDir)
 		if err != nil {
 			t.Error(err)
@@ -242,6 +244,25 @@ func TestCount(t *testing.T) {
 			tt.Errorf("expected retry to be 1 but got %d", count.Retry)
 		}
 	})
+
+	t.Run("should return an empty struct if there is no jobs in the queue", func(tt *testing.T) {
+		os.Remove(dbDir)
+
+		queue, err := queuelite.NewSQLiteQueue(dbDir)
+		if err != nil {
+			t.Error(err)
+		}
+		defer queue.Close()
+
+		count, err := queue.Count(context.Background())
+		if err != nil {
+			tt.Error(err)
+		}
+
+		if count.Total != 0 {
+			tt.Errorf("expected total to be 0 but got %d", count.Total)
+		}
+	})
 }
 
 func TestComplete(t *testing.T) {