我正在为我的StateNotifierProvider编写单元测试，但在测试失败场景时，我遇到了一个奇怪的场景。由于某种原因，单元测试没有捕获初始状态。下面是提供程序实现：

final paymentBundleVM = StateNotifierProvider.autoDispose<PaymentBundleVM, PaymentBundleState>(
  (ref) => PaymentBundleVM(ref.read(getPaymentBundleUseCase), ref.read(createPaymentBundleUseCase)),
  dependencies: [getPaymentBundleUseCase, createPaymentBundleUseCase],
  name: 'paymentBundleVM',
);

class PaymentBundleVM extends StateNotifier<PaymentBundleState> {
  PaymentBundleVM(this._getBundleUseCase, this._createBundleUseCase) : super(PaymentBundleLoading()) {
    unawaited(_loadDependencies());
  }

  final GetPaymentBundleUseCase _getBundleUseCase;
  final CreatePaymentBundleUseCase _createBundleUseCase;

  Future<void> _loadDependencies() async {
    try {
      final bundle = await _getBundleUseCase.run();
      if (mounted) {
        if (bundle != null)
          state = PaymentBundleLoaded(bundle);
        else
          state = PaymentBundleDisabled();
      }
    } on BaseException catch (exception) {
      if (mounted) state = PaymentBundleFailedLoadingState(exception);
    }
  }
}

abstract class PaymentBundleState extends Equatable {
  @override
  List<Object?> get props => [];
}

class PaymentBundleLoading extends PaymentBundleState {}

class PaymentBundleDisabled extends PaymentBundleState {}

class PaymentBundleLoaded extends PaymentBundleState {
  PaymentBundleLoaded(this.bundle);

  final PaymentBundle bundle;

  @override
  List<Object?> get props => [...super.props, bundle];
}

class PaymentBundleFailedLoadingState extends PaymentBundleState {
  PaymentBundleFailedLoadingState(this.exception);

  final BaseException exception;

  @override
  List<Object?> get props => [...super.props, exception];
}

字符串
下面是我的单元测试代码：

void main() {
  final getPaymentBundleUseCaseMock = GetPaymentBundleUseCaseMock();
  final createPaymentBundleUseCaseMock = CreatePaymentBundleUseCaseMock();

  late ProviderContainer container;

  final fakeBundle = PaymentBundleMock();

  setUp(() {
    container = ProviderContainer(
      overrides: [
        getPaymentBundleUseCase.overrideWith((ref) => getPaymentBundleUseCaseMock),
        createPaymentBundleUseCase.overrideWith((ref) => createPaymentBundleUseCaseMock),
      ],
    );
  });

  tearDown(() {
    reset(getPaymentBundleUseCaseMock);
    reset(createPaymentBundleUseCaseMock);
  });

  test('test A', () async {
    when(getPaymentBundleUseCaseMock.run).thenAnswer((_) => Future.value(fakeBundle));
    final listener = ListenerMock<PaymentBundleState>();
    container.listen<PaymentBundleState>(paymentBundleVM, listener, fireImmediately: true);

    await container.pump();

    verifyInOrder(
      [
        () => listener(null, PaymentBundleLoading()),
        () => listener(PaymentBundleLoading(), PaymentBundleLoaded(fakeBundle)),
      ],
    );

    verifyNoMoreInteractions(listener);
  });

  test('test B', () async {
    when(getPaymentBundleUseCaseMock.run).thenAnswer((_) => Future.value());
    final listener = ListenerMock<PaymentBundleState>();
    container.listen<PaymentBundleState>(paymentBundleVM, listener, fireImmediately: true);

    await container.pump();

    verifyInOrder(
      [
        () => listener(null, PaymentBundleLoading()),
        () => listener(PaymentBundleLoading(), PaymentBundleDisabled()),
      ],
    );

    verifyNoMoreInteractions(listener);
  });

  test('test C', () async {
    final exception = HttpException.handshake();
    when(getPaymentBundleUseCaseMock.run).thenThrow(exception);
    final listener = ListenerMock<PaymentBundleState>();
    container.listen<PaymentBundleState>(paymentBundleVM, listener, fireImmediately: true);

    await container.pump();

    verifyInOrder(
      [
        () => listener(null, PaymentBundleLoading()),
        () => listener(PaymentBundleLoading(), PaymentBundleFailedLoadingState(exception)),
      ],
    );

    verifyNoMoreInteractions(listener);
  });
}

型
让我感到奇怪的是，test A和test B都能按预期工作，但第三个却抛出了问题：

Matching call #0 not found. All calls: ListenerMock<PaymentBundleState>.call(
    null,
    PaymentBundleFailedLoadingState(        [BaseException - handshakeHttp] null.
      Server message: null
      User message: null
      
          statusCode: null
        ))

型
因此，基本上这个测试考虑的是StateNotifierProvider的第一个状态是null，之后它直接转换到PaymentBundleFailedLoadingState。问题是，为什么PaymentBundleLoading不在状态栈中考虑，因为它是提供程序示例化时发出的第一个状态？根据我的理解，预期的状态堆栈应该是null -> loading -> failedLoading，而不是null -> failedLoading