如何使用Mockito在Flutter中测试StreamBuilder？

dev_dependencies:
  flutter_test:
    sdk: flutter
  mockito: ^4.1.1

import 'package:flutter/material.dart';

class MyStreamBuilder extends StatelessWidget {
  final Stream<int> stream;

  MyStreamBuilder({required this.stream});

  @override
  Widget build(BuildContext context) {
    return StreamBuilder<int>(
      stream: stream,
      builder: (context, snapshot) {
        if (snapshot.hasData) {
          return Text('Data: ${snapshot.data}');
        } else if (snapshot.hasError) {
          return Text('Error: ${snapshot.error}');
        } else {
          return Text('Loading...');
        }
      },
    );
  }
}

import 'package:flutter_test/flutter_test.dart';
import 'package:mockito/mockito.dart';
import 'package:your_app/my_stream_builder.dart';

class MockStream extends Mock implements Stream<int> {}

void main() {
  testWidgets('Test StreamBuilder with Mockito', (WidgetTester tester) async {
    // 创建一个MockStream实例
    final mockStream = MockStream();

    // 设置MockStream的行为
    when(mockStream.listen(any)).thenAnswer((_) {
      final controller = StreamController<int>();
      controller.add(42);
      return controller.stream.listen(_.positionalArguments[0] as void Function(int)?);
    });

    // 在测试中使用MockStream
    await tester.pumpWidget(MyStreamBuilder(stream: mockStream));

    // 断言是否正确显示了数据
    expect(find.text('Data: 42'), findsOneWidget);
  });
}