new plus button

test/shop_log_test.dart

@@ -0,0 +1,96 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:receipity/models/shop.dart';
+import 'package:receipity/utils/shop_calendar.dart';
+import 'package:receipity/utils/shop_log_filter.dart';
+
+Shop _shop({
+  required int id,
+  required DateTime at,
+  String supermarket = 'Jumbo',
+  String? name,
+  List<String> tags = const [],
+}) {
+  return Shop(
+    id: id,
+    supermarket: supermarket,
+    name: name,
+    shoppedAt: at,
+    total: 10,
+    itemCount: 1,
+    tags: tags,
+  );
+}
+
+void main() {
+  group('monthGrid', () {
+    test('pads August 2026 from Saturday with Monday-first weeks', () {
+      final cells = monthGrid(DateTime(2026, 8));
+      expect(cells.length % 7, 0);
+      expect(cells[0], isNull);
+      expect(cells[1], isNull);
+      expect(cells[2], isNull);
+      expect(cells[3], isNull);
+      expect(cells[4], isNull);
+      expect(cells[5], DateTime(2026, 8, 1));
+      expect(cells[35], DateTime(2026, 8, 31));
+      expect(cells.last, isNull);
+    });
+  });
+
+  test('tripCountsByDay groups multiple trips on the same day', () {
+    final counts = tripCountsByDay([
+      DateTime(2026, 8, 12, 9),
+      DateTime(2026, 8, 12, 18),
+      DateTime(2026, 8, 13),
+    ]);
+    expect(counts[DateTime(2026, 8, 12)], 2);
+    expect(counts[DateTime(2026, 8, 13)], 1);
+    expect(heatmapLevel(0), 0);
+    expect(heatmapLevel(1), 1);
+    expect(heatmapLevel(4), 4);
+    expect(heatmapLevel(9), 4);
+  });
+
+  group('filterShops', () {
+    final shops = [
+      _shop(id: 1, at: DateTime(2026, 8, 12), tags: const ['weekly']),
+      _shop(
+        id: 2,
+        at: DateTime(2026, 8, 13),
+        name: 'Work lunch',
+        tags: const ['work'],
+      ),
+    ];
+    const names = {
+      1: ['Milk', 'Bread'],
+      2: ['Coffee'],
+    };
+
+    test('filters by product name', () {
+      final found = filterShops(
+        shops: shops,
+        productNames: names,
+        query: 'milk',
+      );
+      expect(found.map((shop) => shop.id), [1]);
+    });
+
+    test('filters by selected day', () {
+      final found = filterShops(
+        shops: shops,
+        productNames: names,
+        selectedDay: DateTime(2026, 8, 13),
+      );
+      expect(found.single.id, 2);
+    });
+
+    test('filters by tag', () {
+      final found = filterShops(
+        shops: shops,
+        productNames: names,
+        tag: 'weekly',
+      );
+      expect(found.single.id, 1);
+    });
+  });
+}