test(tests): add comprehensive unit tests for various models and repositories, enhancing test coverage and ensuring correct functionality

test/features/chat/models/chat_user_model_test.dart

@@ -27,6 +27,36 @@ void main() {
 
       expect(model.profilePhotoUrl, isNull);
     });
+
+    test('fromJson создает ChatUserModel из JSON', () {
+      final json = {
+        'id': 1,
+        'name': 'User Name',
+        'slug': 'user-slug',
+        'profile_photo_url': 'https://example.com/photo.jpg',
+      };
+
+      final model = ChatUserModel.fromJson(json);
+
+      expect(model.id, 1);
+      expect(model.name, 'User Name');
+      expect(model.slug, 'user-slug');
+      expect(model.profilePhotoUrl, 'https://example.com/photo.jpg');
+    });
+
+    test('fromJson создает ChatUserModel из JSON без фото', () {
+      final json = {
+        'id': 1,
+        'name': 'User Name',
+        'slug': 'user-slug',
+      };
+
+      final model = ChatUserModel.fromJson(json);
+
+      expect(model.id, 1);
+      expect(model.name, 'User Name');
+      expect(model.profilePhotoUrl, isNull);
+    });
   });
 }