Flutter bloc test -- emitsInorder does not emit the initial state - flutter

Question

I'm really confused of how to get the bloc to emit the initial state. bloc.state emits the latest state. And since there is no #override initialState available in the new bloc library, initialState was passed in to the super constructor. But still bloc does not emit the initialState, which in this case is Empty().
number_trivia_bloc.dart
import 'package:clean_architecture/core/error/failure.dart';
import 'package:clean_architecture/core/utils/input_converter.dart';
import 'package:clean_architecture/features/number_trivia/domain/usecases/get_concrete_number_trivia_repository.dart';
import 'package:clean_architecture/features/number_trivia/domain/usecases/get_random_number_trivia.dart';
import 'package:flutter/cupertino.dart';
import 'package:flutter_bloc/flutter_bloc.dart';
import 'number_trivia_state.dart';
import 'number_trivia_event.dart';
const SERVER_FAILURE = 'Server failure';
const CACHE_FAILURE = 'Cache failure';
const INVALID_INPUT_FAILURE =
'Invalid Input Failure - The input should not be a negative integer or zero';
class NumberTriviaBloc extends Bloc<NumberTriviaEvent, NumberTriviaState> {
final GetConcreteNumberTrivia getConcreteNumberTrivia;
final GetRandomNumberTrivia getRandomNumberTrivia;
final InputConverter inputConverter;
NumberTriviaBloc({
// Changed the name of the constructor parameter (cannot use 'this.')
#required GetConcreteNumberTrivia concrete,
#required GetRandomNumberTrivia random,
#required this.inputConverter,
// Asserts are how you can make sure that a passed in argument is not null.
// We omit this elsewhere for the sake of brevity.
}) : assert(concrete != null),
assert(random != null),
assert(inputConverter != null),
getConcreteNumberTrivia = concrete,
getRandomNumberTrivia = random,
super(Empty());
#override
Stream<NumberTriviaState> mapEventToState(
NumberTriviaEvent event,
) async* {
if (event is GetTriviaForConcreteNumber) {
final inputEither =
inputConverter.stringToUnsignedInteger(event.numberString);
yield* inputEither.fold(
(failure) async* {
yield Error(message: INVALID_INPUT_FAILURE);
},
(integer) async* {
yield Loading();
},
);
}
}
}
number_trivia_bloc_test.dart
import 'package:clean_architecture/core/utils/input_converter.dart';
import 'package:clean_architecture/features/number_trivia/data/models/number_trivia_model.dart';
import 'package:clean_architecture/features/number_trivia/domain/entities/number_trivia.dart';
import 'package:clean_architecture/features/number_trivia/domain/usecases/get_concrete_number_trivia_repository.dart';
import 'package:clean_architecture/features/number_trivia/domain/usecases/get_random_number_trivia.dart';
import 'package:clean_architecture/features/number_trivia/presentation/bloc/number_trivia_bloc.dart';
import 'package:dartz/dartz.dart';
import 'package:flutter_test/flutter_test.dart';
import 'package:clean_architecture/features/number_trivia/presentation/bloc/number_trivia_state.dart';
import 'package:clean_architecture/features/number_trivia/presentation/bloc/number_trivia_event.dart';
import 'package:mockito/mockito.dart';
class MockGetConcreteNumberTrivia extends Mock
implements GetConcreteNumberTrivia {}
class MockGetRandomNumberTrivia extends Mock implements GetRandomNumberTrivia {}
class MockInputConverter extends Mock implements InputConverter {}
void main() {
NumberTriviaBloc bloc;
MockGetConcreteNumberTrivia mockGetConcreteNumberTrivia;
MockGetRandomNumberTrivia mockGetRandomNumberTrivia;
MockInputConverter mockInputConverter;
setUp(() {
mockGetConcreteNumberTrivia = MockGetConcreteNumberTrivia();
mockGetRandomNumberTrivia = MockGetRandomNumberTrivia();
mockInputConverter = MockInputConverter();
bloc = NumberTriviaBloc(
concrete: mockGetConcreteNumberTrivia,
random: mockGetRandomNumberTrivia,
inputConverter: mockInputConverter,
);
});
test('initialState should be Empty', () {
// assert
expect(bloc.state, equals(Empty()));
});
group('GetTriviaForNumber', () {
String str = '1';
int parsedStr = int.parse(str);
NumberTrivia tTrivia =
NumberTriviaModel(text: 'test text', number: parsedStr);
test('Should convert a string to an unsigned integer', () async {
//arrange
when(mockInputConverter.stringToUnsignedInteger(any))
.thenReturn(Right(parsedStr));
//act
bloc.add(GetTriviaForConcreteNumber(str));
await untilCalled(mockInputConverter.stringToUnsignedInteger(str));
//assert
verify(mockInputConverter.stringToUnsignedInteger(any));
});
test('Should return [Error] for InvalidInputFailure', () async {
//arrange
when(mockInputConverter.stringToUnsignedInteger(any))
.thenReturn(Left(InvalidInputFailure()));
//assert later
final expected = [
Empty(),
Error(message: INVALID_INPUT_FAILURE),
];
expectLater(bloc, emitsInOrder(expected));
//act
bloc.add(GetTriviaForConcreteNumber(str));
});
});
}
It should work but all I get is this error screaming at me. I tries bloc.cast(), bloc.asBroadcastStream(). Nothing seems to work.So, please, can someone help me figure this out. Thanks in advance.

Answer 1

There contains some change from flutter_bloc 6.0.0
You can check the initial state via
test('initial state is correct', () {
expect(bloc.state, Empty());
});
Mentioned here:
Regression: initial state is not emited anymore