refactor: update json keys in user pref test

- Use snake_case keys in json

Author: fulleni

test/src/models/user_preferences/user_content_preferences_test.dart

@@ -60,7 +60,7 @@ void main() {
       test('returns correct instance from JSON with all fields', () {
         final json = {
           'id': 'user-1',
-          'followedCountries': [
+          'followed_countries': [
             {
               'id': 'country-1',
               'iso_code': 'US',
@@ -70,30 +70,30 @@ void main() {
               'action': defaultAction.toJson(),
             },
           ],
-          'followedSources': [
+          'followed_sources': [
             {
               'id': 'source-1',
               'name': 'Example News',
               'url': 'http://example.com',
               'type': 'source',
-              'sourceType': 'news-agency',
+              'source_type': 'news_agency',
               'action': defaultAction.toJson(),
             },
           ],
-          'followedCategories': [
+          'followed_categories': [
             {
               'id': 'category-1',
               'name': 'Technology',
               'type': 'category',
               'action': defaultAction.toJson(),
             },
           ],
-          'savedHeadlines': [
+          'saved_headlines': [
             {
               'id': 'headline-1',
               'title': 'Example Headline',
               'url': 'http://example.com/headline',
-              'publishedAt': '2023-01-01T00:00:00.000Z',
+              'published_at': '2023-01-01T00:00:00.000Z',
               'type': 'headline',
               'action': defaultAction.toJson(),
             },
@@ -116,10 +116,10 @@ void main() {
       test('returns correct instance from JSON with empty lists', () {
         final json = {
           'id': 'user-3',
-          'followedCountries': [],
-          'followedSources': [],
-          'followedCategories': [],
-          'savedHeadlines': [],
+          'followed_countries': [],
+          'followed_sources': [],
+          'followed_categories': [],
+          'saved_headlines': [],
         };
 
         final result = UserContentPreferences.fromJson(json);
@@ -135,7 +135,7 @@ void main() {
           () {
         final json = {
           'id': 'user-4',
-          // Missing followedCountries, followedSources, followedCategories, savedHeadlines
+          // Missing followed_countries, followed_sources, followed_categories, saved_headlines
         };
 
         final result = UserContentPreferences.fromJson(json);
@@ -157,29 +157,29 @@ void main() {
         final json = preferencesWithSaved.toJson();
 
         expect(json['id'], 'user-1');
-        expect(json['followedCountries'], isA<List>());
-        expect((json['followedCountries'] as List).length, 1);
-        expect((json['followedCountries'] as List).first['id'], 'country-1');
-        expect(json['followedSources'], isA<List>());
-        expect((json['followedSources'] as List).length, 1);
-        expect((json['followedSources'] as List).first['id'], 'source-1');
-        expect(json['followedCategories'], isA<List>());
-        expect((json['followedCategories'] as List).length, 1);
-        expect((json['followedCategories'] as List).first['id'], 'category-1');
-        expect(json['savedHeadlines'], isA<List>());
-        expect((json['savedHeadlines'] as List).length, 1);
-        expect((json['savedHeadlines'] as List).first['id'], 'headline-1');
+        expect(json['followed_countries'], isA<List>());
+        expect((json['followed_countries'] as List).length, 1);
+        expect((json['followed_countries'] as List).first['id'], 'country-1');
+        expect(json['followed_sources'], isA<List>());
+        expect((json['followed_sources'] as List).length, 1);
+        expect((json['followed_sources'] as List).first['id'], 'source-1');
+        expect(json['followed_categories'], isA<List>());
+        expect((json['followed_categories'] as List).length, 1);
+        expect((json['followed_categories'] as List).first['id'], 'category-1');
+        expect(json['saved_headlines'], isA<List>());
+        expect((json['saved_headlines'] as List).length, 1);
+        expect((json['saved_headlines'] as List).first['id'], 'headline-1');
       });
 
       test('returns correct JSON map with empty lists', () {
         const emptyPreferences = UserContentPreferences(id: 'user-5');
         final json = emptyPreferences.toJson();
 
         expect(json['id'], 'user-5');
-        expect(json['followedCountries'], isEmpty);
-        expect(json['followedSources'], isEmpty);
-        expect(json['followedCategories'], isEmpty);
-        expect(json['savedHeadlines'], isEmpty);
+        expect(json['followed_countries'], isEmpty);
+        expect(json['followed_sources'], isEmpty);
+        expect(json['followed_categories'], isEmpty);
+        expect(json['saved_headlines'], isEmpty);
       });
     });