Chore: rememberDevice API Unit Test suite (#5108)

chore: add rememberdevice unit test

packages/auth/amplify_auth_cognito_test/test/plugin/remember_device_test.dart

@@ -0,0 +1,86 @@
+// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+import 'package:amplify_auth_cognito_dart/amplify_auth_cognito_dart.dart';
+import 'package:amplify_auth_cognito_dart/src/credentials/cognito_keys.dart';
+import 'package:amplify_auth_cognito_dart/src/credentials/device_metadata_repository.dart';
+import 'package:amplify_auth_cognito_dart/src/sdk/cognito_identity_provider.dart';
+import 'package:amplify_auth_cognito_dart/src/state/cognito_state_machine.dart';
+import 'package:amplify_auth_cognito_test/common/mock_clients.dart';
+import 'package:amplify_auth_cognito_test/common/mock_config.dart';
+import 'package:amplify_auth_cognito_test/common/mock_secure_storage.dart';
+import 'package:amplify_core/amplify_core.dart';
+import 'package:test/test.dart';
+
+enum DeviceState { untracked, tracked, remembered }
+
+void main() {
+  AmplifyLogger().logLevel = LogLevel.verbose;
+
+  final userPoolKeys = CognitoUserPoolKeys(userPoolConfig);
+  final identityPoolKeys = CognitoIdentityPoolKeys(identityPoolConfig);
+  final testAuthRepo = AmplifyAuthProviderRepository();
+  final mockUpdateDeviceStatusResponse = UpdateDeviceStatusResponse();
+
+  late DeviceMetadataRepository repo;
+  late AmplifyAuthCognitoDart plugin;
+  late CognitoAuthStateMachine stateMachine;
+  late MockSecureStorage secureStorage;
+
+  Future<DeviceState> getDeviceState() async {
+    final secrets = await repo.get(username);
+    if (secrets == null) {
+      return DeviceState.untracked;
+    }
+    return secrets.deviceStatus == DeviceRememberedStatusType.remembered
+        ? DeviceState.remembered
+        : DeviceState.tracked;
+  }
+
+  group('rememberDevice', () {
+    setUp(() async {
+      secureStorage = MockSecureStorage();
+      seedStorage(
+        secureStorage,
+        userPoolKeys: userPoolKeys,
+        identityPoolKeys: identityPoolKeys,
+        deviceKeys: CognitoDeviceKeys(userPoolConfig, username),
+      );
+      plugin = AmplifyAuthCognitoDart(
+        secureStorageFactory: (_) => secureStorage,
+      );
+      stateMachine = plugin.stateMachine;
+      await plugin.configure(
+        config: mockConfig,
+        authProviderRepo: testAuthRepo,
+      );
+      final mockIdp = MockCognitoIdentityProviderClient(
+        forgetDevice: () async {},
+        updateDeviceStatus: () async => mockUpdateDeviceStatusResponse,
+      );
+      stateMachine.addInstance<CognitoIdentityProviderClient>(mockIdp);
+      repo = stateMachine.getOrCreate<DeviceMetadataRepository>();
+    });
+
+    tearDown(() async {
+      await plugin.close();
+    });
+
+    test('rememberDevice changes the device state from tracked to remembered',
+        () async {
+      expect(await getDeviceState(), DeviceState.tracked);
+      await plugin.rememberDevice();
+      expect(await getDeviceState(), DeviceState.remembered);
+    });
+
+    test(
+        'rememberDevice throws a DeviceNotTrackedException when device is forgotten',
+        () async {
+      await plugin.forgetDevice();
+      await expectLater(
+        plugin.rememberDevice,
+        throwsA(isA<DeviceNotTrackedException>()),
+      );
+    });
+  });
+}