feat(tests): updated tests coverage to 66.5%

test/features/create_plan/models/plan_slug_model_test.dart

@@ -0,0 +1,29 @@
+import 'package:eatvio_app/features/create_plan/models/plan_slug_model.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  group('PlanSlugModel', () {
+    test('fromJson parses slug correctly', () {
+      final json = {'slug': 'test-plan-slug'};
+
+      final model = PlanSlugModel.fromJson(json);
+
+      expect(model.slug, 'test-plan-slug');
+    });
+
+    test('toJson serializes slug correctly', () {
+      final model = PlanSlugModel(slug: 'test-plan-slug');
+
+      final json = model.toJson();
+
+      expect(json['slug'], 'test-plan-slug');
+    });
+
+    test('creates instance with slug', () {
+      final model = PlanSlugModel(slug: 'another-slug');
+
+      expect(model.slug, 'another-slug');
+    });
+  });
+}
+