feat(tests): updated tests coverage to 66.5%

test/features/diary/models/diary_index_model_test.dart

@@ -0,0 +1,29 @@
+import 'package:eatvio_app/features/diary/models/diary_index_model.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  group('DiaryIndexModel', () {
+    test('fromJson parses id correctly', () {
+      final json = {'id': 123};
+
+      final model = DiaryIndexModel.fromJson(json);
+
+      expect(model.id, 123);
+    });
+
+    test('toJson serializes id correctly', () {
+      const model = DiaryIndexModel(id: 123);
+
+      final json = model.toJson();
+
+      expect(json['id'], 123);
+    });
+
+    test('creates instance with id', () {
+      const model = DiaryIndexModel(id: 456);
+
+      expect(model.id, 456);
+    });
+  });
+}
+