Testing Patterns

Unit Tests (Domain & Data Layers)

Use Case Testing

import 'package:flutter_test/flutter_test.dart'; import 'package:mocktail/mocktail.dart'; import 'package:dartz/dartz.dart';

class MockUserRepository extends Mock implements UserRepository {}

void main() { late GetUser useCase; late MockUserRepository mockRepository;

setUp(() { mockRepository = MockUserRepository(); useCase = GetUser(mockRepository); });

group('GetUser', () { final tUser = User( id: '1', name: 'Test User', email: 'test@example.com', createdAt: DateTime(2024), );

test('should return user when repository call is successful', () async {
  // Arrange
  when(() => mockRepository.getUser('1'))
      .thenAnswer((_) async => Right(tUser));

  // Act
  final result = await useCase('1');

  // Assert
  expect(result, Right(tUser));
  verify(() => mockRepository.getUser('1')).called(1);
  verifyNoMoreInteractions(mockRepository);
});

test('should return ServerFailure when repository fails', () async {
  // Arrange
  when(() => mockRepository.getUser('1'))
      .thenAnswer((_) async => Left(ServerFailure('Error')));

  // Act
  final result = await useCase('1');

  // Assert
  expect(result, isA<Left>());
  verify(() => mockRepository.getUser('1')).called(1);
});

}); }

Repository Testing

class MockUserProvider extends Mock implements UserProvider {} class MockUserLocalSource extends Mock implements UserLocalSource {} class MockNetworkInfo extends Mock implements NetworkInfo {}

void main() { late UserRepositoryImpl repository; late MockUserProvider mockProvider; late MockUserLocalSource mockLocalSource; late MockNetworkInfo mockNetworkInfo;

setUp(() { mockProvider = MockUserProvider(); mockLocalSource = MockUserLocalSource(); mockNetworkInfo = MockNetworkInfo(); repository = UserRepositoryImpl( mockProvider, mockLocalSource, mockNetworkInfo, ); });

group('getUser', () { final tUserModel = UserModel( id: '1', name: 'Test', email: 'test@example.com', createdAt: DateTime(2024), );

test('should return remote data when online', () async {
  // Arrange
  when(() => mockNetworkInfo.isConnected).thenAnswer((_) async => true);
  when(() => mockProvider.fetchUser('1'))
      .thenAnswer((_) async => tUserModel);
  when(() => mockLocalSource.cacheUser(tUserModel))
      .thenAnswer((_) async => {});

  // Act
  final result = await repository.getUser('1');

  // Assert
  verify(() => mockProvider.fetchUser('1'));
  verify(() => mockLocalSource.cacheUser(tUserModel));
  expect(result, Right(tUserModel.toEntity()));
});

test('should return cached data when offline', () async {
  // Arrange
  when(() => mockNetworkInfo.isConnected).thenAnswer((_) async => false);
  when(() => mockLocalSource.getCachedUser('1'))
      .thenAnswer((_) async => tUserModel);

  // Act
  final result = await repository.getUser('1');

  // Assert
  verify(() => mockLocalSource.getCachedUser('1'));
  verifyNever(() => mockProvider.fetchUser('1'));
  expect(result, Right(tUserModel.toEntity()));
});

}); }

Controller Testing

class MockGetUser extends Mock implements GetUser {}

void main() { late UserController controller; late MockGetUser mockGetUser;

setUp(() { mockGetUser = MockGetUser(); controller = UserController(getUserUseCase: mockGetUser); });

tearDown(() { controller.dispose(); });

group('UserController', () { final tUser = User( id: '1', name: 'Test', email: 'test@example.com', createdAt: DateTime(2024), );

test('initial state should be empty', () {
  expect(controller.user, null);
  expect(controller.isLoading, false);
  expect(controller.error, null);
});

test('should load user successfully', () async {
  // Arrange
  when(() => mockGetUser('1')).thenAnswer((_) async => Right(tUser));

  // Act
  await controller.loadUser('1');

  // Assert
  expect(controller.user, tUser);
  expect(controller.isLoading, false);
  expect(controller.error, null);
});

test('should handle error', () async {
  // Arrange
  when(() => mockGetUser('1'))
      .thenAnswer((_) async => Left(ServerFailure('Error')));

  // Act
  await controller.loadUser('1');

  // Assert
  expect(controller.user, null);
  expect(controller.isLoading, false);
  expect(controller.error, isNotNull);
});

}); }

Widget Tests

void main() { testWidgets('UserPage displays loading indicator', (tester) async { // Arrange final mockController = MockUserController(); when(() => mockController.isLoading).thenReturn(true); when(() => mockController.user).thenReturn(null); when(() => mockController.error).thenReturn(null);

Get.put<UserController>(mockController);

// Act
await tester.pumpWidget(
  GetMaterialApp(home: UserPage()),
);

// Assert
expect(find.byType(CircularProgressIndicator), findsOneWidget);

// Cleanup
Get.delete<UserController>();

});

testWidgets('UserPage displays user data', (tester) async { // Arrange final tUser = User( id: '1', name: 'John Doe', email: 'john@example.com', createdAt: DateTime(2024), );

final mockController = MockUserController();
when(() => mockController.isLoading).thenReturn(false);
when(() => mockController.user).thenReturn(tUser);
when(() => mockController.error).thenReturn(null);

Get.put<UserController>(mockController);

// Act
await tester.pumpWidget(
  GetMaterialApp(home: UserPage()),
);

// Assert
expect(find.text('John Doe'), findsOneWidget);
expect(find.text('john@example.com'), findsOneWidget);

// Cleanup
Get.delete<UserController>();

});

testWidgets('UserPage displays error', (tester) async { // Arrange final mockController = MockUserController(); when(() => mockController.isLoading).thenReturn(false); when(() => mockController.user).thenReturn(null); when(() => mockController.error).thenReturn('Server error');

Get.put<UserController>(mockController);

// Act
await tester.pumpWidget(
  GetMaterialApp(home: UserPage()),
);

// Assert
expect(find.text('Server error'), findsOneWidget);
expect(find.byIcon(Icons.error_outline), findsOneWidget);

// Cleanup
Get.delete<UserController>();

}); }

Integration Tests

void main() { IntegrationTestWidgetsFlutterBinding.ensureInitialized();

group('User Flow Integration Tests', () { testWidgets('complete user login flow', (tester) async { // Start app await tester.pumpWidget(MyApp()); await tester.pumpAndSettle();

  // Navigate to login
  await tester.tap(find.text('Login'));
  await tester.pumpAndSettle();

  // Enter credentials
  await tester.enterText(find.byType(TextField).at(0), 'test@example.com');
  await tester.enterText(find.byType(TextField).at(1), 'password');
  await tester.pumpAndSettle();

  // Submit
  await tester.tap(find.text('Submit'));
  await tester.pumpAndSettle();

  // Verify navigation to home
  expect(find.text('Home'), findsOneWidget);
});

}); }

Golden Tests

void main() { testWidgets('UserCard golden test', (tester) async { final tUser = User( id: '1', name: 'John Doe', email: 'john@example.com', createdAt: DateTime(2024), );

await tester.pumpWidget(
  MaterialApp(
    home: Scaffold(
      body: UserCard(user: tUser),
    ),
  ),
);

await expectLater(
  find.byType(UserCard),
  matchesGoldenFile('goldens/user_card.png'),
);

}); }