使用颤动bloc_test测试特定状态

import 'package:bloc/bloc.dart';

part 'counter_event.dart';
part 'counter_state.dart';

class CounterBloc extends Bloc<CounterEvent, CounterState> {
  CounterBloc() : super(CounterInitial());

  @override
  Stream<CounterState> mapEventToState(CounterEvent event) async* {
    if (event is Increment) {
      yield CounterIncreased(state.count + 1);
    } else if (event is Decrement) {
      yield CounterDecreased(state.count - 1);
    }
  }
}

part of 'counter_bloc.dart';

abstract class CounterEvent extends Equatable {
  const CounterEvent();

  @override
  List<Object> get props => [];
}

class Increment extends CounterEvent {}

class Decrement extends CounterEvent {}

part of 'counter_bloc.dart';

abstract class CounterState extends Equatable {
  const CounterState();

  @override
  List<Object> get props => [];
}

class CounterInitial extends CounterState {}

class CounterIncreased extends CounterState {
  final int count;

  const CounterIncreased(this.count);

  @override
  List<Object> get props => [count];
}

class CounterDecreased extends CounterState {
  final int count;

  const CounterDecreased(this.count);

  @override
  List<Object> get props => [count];
}

import 'package:bloc_test/bloc_test.dart';
import 'package:flutter_test/flutter_test.dart';
import 'package:your_app/counter_bloc.dart';

void main() {
  group('CounterBloc', () {
    final counterBloc = CounterBloc();

    blocTest<CounterEvent, CounterState>(
      'emits [CounterIncreased] when Increment is added',
      build: () => counterBloc,
      act: (bloc) => bloc.add(Increment()),
      expect: () => [CounterIncreased(1)],
    );

    blocTest<CounterEvent, CounterState>(
      'emits [CounterDecreased] when Decrement is added',
      build: () => counterBloc,
      act: (bloc) => bloc.add(Decrement()),
      expect: () => [CounterDecreased(0)],
    );
  });
}

final counterBloc = CounterBloc();
counterBloc.add(Increment());

BlocListener<CounterBloc, CounterState>(
  listener: (context, state) {
    print(state);
  },
  child: YourWidget(),
);