Testing sample (#500)

testing_app/test_driver/state_mgmt_test.dart

@@ -0,0 +1,45 @@
+// 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_driver/flutter_driver.dart';
+import 'package:test/test.dart';
+
+void main() {
+  group('Testing App State Management Tests', () {
+    FlutterDriver driver;
+
+    // Connect to the Flutter driver before running any tests.
+    setUpAll(() async {
+      driver = await FlutterDriver.connect();
+    });
+
+    // Close the connection to the driver after the tests have completed.
+    tearDownAll(() async {
+      if (driver != null) {
+        await driver.close();
+      }
+    });
+
+    test('Verifying add method', () async {
+      /// This function is used for communication between
+      /// the driver and the application.
+      /// The [enableFlutterDriverExtension] call must have a [DataHandler]
+      /// callback to handle these requests.
+      /// We are currently using it to perform operations on the provider.
+      /// Specifically, send 'ADD' command to the handler in this case.
+      await driver.requestData('ADD');
+
+      // Check if the new item apppears in the list.
+      await driver.waitFor(find.text('Item 30'));
+    });
+
+    test('Verifying remove method', () async {
+      /// Peform remove operation on the provider using the [DataHandler].
+      await driver.requestData('REMOVE');
+
+      // Verify if it disappears.
+      await driver.waitForAbsent(find.text('Item 30'));
+    });
+  });
+}