mogen_unit_tests 1.0.8

Scans Riverpod AsyncNotifier classes and auto-generates Mocktail unit tests.

mogen_unit_tests

A CLI tool that scans your Flutter feature folders, reads your Riverpod AsyncNotifier / Notifier classes, detects repository dependencies, and auto-generates Mocktail-based unit tests with success and error cases for every method.

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What it generates

For every notifier it finds, the tool produces a ready-to-run test file with:

• Mock<Repository> classes for every detected dependency
• Fake<Type> classes + registerFallbackValue for every complex parameter type
• A ProviderContainer with repository provider overrides in setUp
• container.dispose() in tearDown
• A build() group with a success test and an error test
• A group per public method, each with a success test and an error test

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Expected folder structure

The tool expects this layout inside your Flutter project:

lib/
└── features/
    └── cart/                          ← feature name (any name)
        └── presentation/
            ├── notifiers/
            │   └── cart_notifier.dart ← your AsyncNotifier lives here
            └── states/
                └── cart_state.dart    ← optional, used to infer field types

Generated tests are written to:

test/
└── unit/
    └── features/
        └── cart/
            └── cart_notifier_test.dart

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Installation

Add to your Flutter project's pubspec.yaml under dev_dependencies:

dev_dependencies:
    mogen_unit_tests: ^1.0.8

Then run:

dart pub get

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Usage

From the root of your Flutter project:

dart run mogen_unit_tests

Options

Flag	Short	Default	Description
--root	-r	.	Project root directory
--dry-run	-d	false	Preview what would be generated without writing files
--verbose	-v	false	Print detailed progress
--version			Print version and exit
--help	-h		Show help

Examples

# Normal run from project root
dart run mogen_unit_tests

# Preview without writing any files
dart run mogen_unit_tests --dry-run --verbose

# Run from a different directory
dart run mogen_unit_tests --root /path/to/my_project

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Example input and output

Your notifier (lib/features/cart/presentation/notifiers/cart_notifier.dart)

@riverpod
class CartNotifier extends _$CartNotifier {
  @override
  Future<CartState> build() async {
    final repo = ref.read(cartRepositoryProvider);
    return repo.fetchCart();
  }

  Future<void> addItem(CartItem item) async {
    final repo = ref.read(cartRepositoryProvider);
    await repo.addItem(item);
    ref.invalidateSelf();
  }

  Future<void> clearCart() async {
    final repo = ref.read(cartRepositoryProvider);
    await repo.clearCart();
    ref.invalidateSelf();
  }
}

Your state (lib/features/cart/presentation/states/cart_state.dart)

class CartState {
  final List<CartItem> items;
  final double total;

  const CartState({required this.items, required this.total});
}

Generated test (test/features/cart/presentation/notifiers/cart_notifier_test.dart)

// GENERATED BY mogen_unit_tests — DO NOT EDIT

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

import 'package:my_app/features/cart/presentation/notifiers/cart_notifier.dart';
import 'package:my_app/features/cart/presentation/states/cart_state.dart';
// TODO: import the file that declares CartRepository

// ── Mocks ─────────────────────────────────────────────────────────────────
class MockCartRepository extends Mock implements CartRepository {}

// ── Fakes (registerFallbackValue) ─────────────────────────────────────────
class FakeCartItem extends Fake implements CartItem {}

void main() {
  group('CartNotifier', () {
    late MockCartRepository mockCartRepository;
    late ProviderContainer container;

    setUpAll(() {
      registerFallbackValue(FakeCartItem());
    });

    setUp(() {
      mockCartRepository = MockCartRepository();

      container = ProviderContainer(
        overrides: [
          cartRepositoryProvider.overrideWithValue(mockCartRepository),
        ],
      );
    });

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

    // ── build() ─────────────────────────────────────────────────────────
    group('build', () {
      test('returns CartState successfully', () async {
        // Arrange: stub repositories
        // when(() => mockCartRepository.someMethod(any()))
        //     .thenAnswer((_) async => CartState(...));

        // Act
        final result = await container.read(cartNotifierProvider.future);

        // Assert
        expect(result, isA<CartState>());
      });

      test('emits error when repository throws', () async {
        // when(() => mockCartRepository.someMethod(any()))
        //     .thenThrow(Exception('test error'));

        await container
            .read(cartNotifierProvider.future)
            .catchError((_) => FakeCartState());

        expect(container.read(cartNotifierProvider), isA<AsyncError>());
      });
    });

    // ── addItem() ────────────────────────────────────────────────────────
    group('addItem', () {
      test('addItem completes successfully', () async {
        // Arrange: inputs
        final item = FakeCartItem();

        await container.read(cartNotifierProvider.future);

        // Act
        await container.read(cartNotifierProvider.notifier).addItem(item);

        // Assert
        // verify(() => mockCartRepository.someMethod(any())).called(1);
      });

      test('addItem handles error from repository', () async {
        // when(() => mockCartRepository.someMethod(any()))
        //     .thenThrow(Exception('test error'));
        final item = FakeCartItem();

        await container.read(cartNotifierProvider.future).catchError((_) {});

        expect(
          () async => container.read(cartNotifierProvider.notifier).addItem(item),
          throwsA(isA<Exception>()),
        );
      });
    });

    // ── clearCart() ──────────────────────────────────────────────────────
    group('clearCart', () {
      test('clearCart completes successfully', () async {
        await container.read(cartNotifierProvider.future);

        await container.read(cartNotifierProvider.notifier).clearCart();

        // verify(() => mockCartRepository.someMethod(any())).called(1);
      });

      test('clearCart handles error from repository', () async {
        // when(() => mockCartRepository.someMethod(any()))
        //     .thenThrow(Exception('test error'));

        await container.read(cartNotifierProvider.future).catchError((_) {});

        expect(
          () async => container.read(cartNotifierProvider.notifier).clearCart(),
          throwsA(isA<Exception>()),
        );
      });
    });
  });
}

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After generation

The only lines you need to fill in manually are the when() stubs, since the tool reads your notifier but not your repository interface. Each stub is clearly marked:

// when(() => mockCartRepository.fetchCart())
//     .thenAnswer((_) async => CartState(items: [], total: 0));

Uncomment and replace someMethod with the real method name from your repository. Everything else runs as-is.

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Supported notifier types

Class	Detected
AsyncNotifier<T>	✅
AutoDisposeAsyncNotifier<T>	✅
Notifier<T>	✅
AutoDisposeNotifier<T>	✅

Repository dependencies are detected via ref.read(someRepositoryProvider) and ref.watch(someRepositoryProvider) calls inside the notifier body.

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Limitations

• Only generates unit tests — no widget or integration tests
• Repository when() stubs are scaffolded as comments; method names must be filled in manually
• Requires notifiers to live in presentation/notifiers/ — other paths are ignored
• Does not support family notifiers with arguments yet

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Dependencies

Package	Used for
analyzer	Dart AST parsing (no build runner needed)
dart_style	Formatting generated test files
args	CLI flag parsing
glob	Recursive file discovery
path	Cross-platform path manipulation
yaml	Reading pubspec.yaml for package name