ChangeNotifierProviderSample fix:

  - Load todos when the app is first launched, not any time a listener is added
  - Test loading of the todos from the repository

Author: brianegan

change_notifier_provider/lib/app.dart

@@ -23,7 +23,7 @@ class ProviderApp extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
     return ChangeNotifierProvider(
-      create: (_) => TodoListModel(repository: repository),
+      create: (_) => TodoListModel(repository: repository)..loadTodos(),
       child: MaterialApp(
         theme: ArchSampleTheme.theme,
         localizationsDelegates: [

change_notifier_provider/lib/todo_list_model.dart

@@ -39,13 +39,6 @@ class TodoListModel extends ChangeNotifier {
   })  : _todos = todos ?? [],
         _filter = filter ?? VisibilityFilter.all;
 
-  @override
-  void addListener(VoidCallback listener) {
-    super.addListener(listener);
-    // update data for every subscriber, especially for the first one
-    loadTodos();
-  }
-
   /// Loads remote data
   ///
   /// Call this initially and when the user manually refreshes

change_notifier_provider/pubspec.yaml

@@ -17,7 +17,7 @@ environment:
   sdk: ">=2.6.0 <3.0.0"
 
 dependencies:
-  provider: ^4.0.1
+  provider: ^4.0.4
   todos_repository_local_storage:
     path: ../todos_repository_local_storage
   todos_app_core:

…tifier_provider/test/app_state_test.dart …_provider/test/todo_list_model_test.dartchange_notifier_provider/test/app_state_test.dart renamed to change_notifier_provider/test/todo_list_model_test.dart change_notifier_provider/test/app_state_test.dart renamed to change_notifier_provider/test/todo_list_model_test.dart

@@ -141,5 +141,23 @@ void main() {
       expect(model.todos, [todo1, update, todo3]);
       expect(repository.saveCount, 1);
     });
+
+    test('should load todos from the repository', () async {
+      final todos = [Todo('a'), Todo('b'), Todo('c', complete: true)];
+      final repository = MockRepository(todos);
+      final model = TodoListModel(repository: repository);
+
+      expect(model.isLoading, isFalse);
+      expect(model.todos, []);
+
+      final loading = model.loadTodos();
+
+      expect(model.isLoading, isTrue);
+
+      await loading;
+
+      expect(model.isLoading, isFalse);
+      expect(model.todos, todos);
+    });
   });
 }