parser logic added

test/backup_format_test.dart

@@ -3,8 +3,8 @@ import 'package:receipity/services/backup_format.dart';
 
 void main() {
   test('round-trips a backup document', () {
-    final original = const BackupDocument(
-      version: 1,
+    const original = BackupDocument(
+      version: 2,
       exportedAt: '2026-08-29T12:00:00.000',
       darkMode: true,
       supermarkets: [
@@ -46,6 +46,24 @@ void main() {
           'unit_price': 1.5,
         },
       ],
+      shoppingLists: [
+        {
+          'id': 1,
+          'name': 'Weekly',
+          'created_at': '2026-08-29T12:00:00.000',
+          'updated_at': '2026-08-29T12:00:00.000',
+        },
+      ],
+      shoppingListItems: [
+        {
+          'id': 1,
+          'list_id': 1,
+          'product_id': 1,
+          'name': 'Milk',
+          'checked': 0,
+          'sort_order': 0,
+        },
+      ],
       images: {'products/product_1.jpg': 'abc123'},
     );
 
@@ -54,9 +72,31 @@ void main() {
     expect(parsed.products.single['name'], 'Milk');
     expect(parsed.shops.single['id'], 8);
     expect(parsed.shopItems.single['product_id'], 1);
+    expect(parsed.shoppingLists.single['name'], 'Weekly');
+    expect(parsed.shoppingListItems.single['name'], 'Milk');
     expect(parsed.images['products/product_1.jpg'], 'abc123');
   });
 
+  test('accepts a version 1 backup without shopping lists', () {
+    const json = '''
+{
+  "format": "receipity-backup",
+  "version": 1,
+  "exportedAt": "2026-08-29T12:00:00.000",
+  "darkMode": false,
+  "supermarkets": [],
+  "products": [],
+  "shops": [],
+  "shopItems": [],
+  "images": {}
+}
+''';
+    final parsed = BackupDocument.parse(json);
+    expect(parsed.version, 1);
+    expect(parsed.shoppingLists, isEmpty);
+    expect(parsed.shoppingListItems, isEmpty);
+  });
+
   test('rejects a file that is not a Receipity backup', () {
     expect(
       () => BackupDocument.parse('{"hello":"world"}'),