Testing sample (#500)

testing_app/lib/screens/favorites.dart

@@ -0,0 +1,64 @@
+// Copyright 2020 The Flutter team. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:flutter/material.dart';
+import 'package:provider/provider.dart';
+import 'package:testing_app/models/favorites.dart';
+
+class FavoritesPage extends StatelessWidget {
+  static String routeName = '/favorites_page';
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      appBar: AppBar(
+        title: Text('Favorites'),
+      ),
+      body: Consumer<Favorites>(
+        builder: (context, value, child) => ListView.builder(
+          itemCount: value.items.length,
+          padding: const EdgeInsets.symmetric(vertical: 16),
+          itemBuilder: (context, index) => FavoriteItemTile(value.items[index]),
+        ),
+      ),
+    );
+  }
+}
+
+class FavoriteItemTile extends StatelessWidget {
+  final int itemNo;
+
+  const FavoriteItemTile(
+    this.itemNo,
+  );
+
+  @override
+  Widget build(BuildContext context) {
+    return Padding(
+      padding: const EdgeInsets.all(8.0),
+      child: ListTile(
+        leading: CircleAvatar(
+          backgroundColor: Colors.primaries[itemNo % Colors.primaries.length],
+        ),
+        title: Text(
+          'Item $itemNo',
+          key: Key('favorites_text_$itemNo'),
+        ),
+        trailing: IconButton(
+          key: Key('remove_icon_$itemNo'),
+          icon: Icon(Icons.close),
+          onPressed: () {
+            Provider.of<Favorites>(context, listen: false).remove(itemNo);
+            Scaffold.of(context).showSnackBar(
+              SnackBar(
+                content: Text('Removed from favorites.'),
+                duration: Duration(seconds: 1),
+              ),
+            );
+          },
+        ),
+      ),
+    );
+  }
+}