在mapEventToState中使用yield和Either时，测试我的bloc失败

问题描述

我正在学习有关干净架构的课程，并且遇到以下错误。

以下测试失败。

test('should emit [Error] when the input is invalid',() async {
  final tNumberString = '1';
  when(mockInputConverter.stringToUnsignedInteger(any))
    .thenReturn(Left(InvalidInputFailure()));

  final expected = [
    Empty(),Error(message: invalidInput),];
   expectLater(bloc.state,emitsInorder(expected));

   bloc.add(GetTriviaForConcreteNumberEvent(tNumberString));
});

我的NumberTriviaBloc如下

part 'number_trivia_event.dart';
part 'number_trivia_state.dart';

const String serverFailureMessage = 'Server Failure';
const String cacheFailureMessage = 'Cache Failure';
const String invalidInput =
    'Invalid input - the number should be a positive integer';

class NumberTriviaBloc extends Bloc<NumberTriviaEvent,NumberTriviaState> {
  NumberTriviaBloc(
      {@required GetConcreteNumberTrivia concrete,@required GetRandomNumberTrivia random,@required this.inputConverter})
      : assert(concrete != null),assert(random != null),assert(inputConverter != null),_getConcreteNumberTrivia = concrete,_getRandomNumberTrivia = random,super(Empty());

  final GetConcreteNumberTrivia _getConcreteNumberTrivia;
  final GetRandomNumberTrivia _getRandomNumberTrivia;
  final InputConverter inputConverter;

  @override
  Stream<NumberTriviaState> mapEventToState(
    NumberTriviaEvent event,) async* {
    if (event is GetTriviaForConcreteNumberEvent) {
      final inputEither =
          inputConverter.stringToUnsignedInteger(event.numberString);

      yield* inputEither.fold(
        (l) async* {
          yield Error(message: invalidInput);
        },(r) => throw UnimplementedError(),);
    }
  }
}

我不太熟悉集团模式以及流和状态的测试机制。我猜测由于失败消息如下，导致代码无法正确执行

ERROR: Expected: should do the following in order:
emit an event that Empty:<Empty>
emit an event that Error:<Error>
Actual: Empty:<Empty>
Which: was not a Stream or a StreamQueue

解决方法

所以我自己解决了。问题中的代码对旧版本的dart有效。目前

import org.apache.livy._
import org.apache.spark.sql.SparkSession

class Test extends Job[Int]{

  override def call(jc: JobContext): Int = {
  
    val spark = jc.sparkSession()

    val logFile = "file:///root/spark/README.md"
    val logData = spark.read.textFile(logFile).cache()
    val numAs = logData.filter(line => line.contains("a")).count()
    val numBs = logData.filter(line => line.contains("b")).count()
    println(s"Lines with a: $numAs,Lines with b: $numBs")
    
    1 //Return value
  }
}

将破坏代码。代替

bloc.state

应该用来获取状态。

第二个问题是不再有

bloc

在Either对象的fold方法中。无论哪种情况都将引发异常。 fold调用的正确功能中必须包含一些非异常逻辑。

修改内容反映在下面的代码中。

number_trivia_bloc_test.dart

throw UnimplementedError();

number_trivia_bloc.dart

test('should emit [Error] when the input is invalid',() async {
  when(mockInputConverter.stringToUnsignedInteger(any))
      .thenReturn(Left(InvalidInputFailure()));

  bloc.add(GetTriviaForConcreteNumberEvent(tNumberString));

  final expected = [
    Error(message: invalidInput),];
  expectLater(bloc,emitsInOrder(expected));
});

bloc dart yield