如何在单元测试(Flutter)中测试流在时间间隔内发出的任何内容？

import 'package:flutter_test/flutter_test.dart';
import 'package:rxdart/rxdart.dart';
import 'package:async/async.dart';

testWidgets('test stream emits any content within time interval', (WidgetTester tester) async {
  // 测试代码
});

final controller = StreamController<String>();
final stream = controller.stream;

final observable = Observable(stream).takeWhile((_) => !timeout.hasExpired);

final completer = Completer();

observable.listen((data) {
  // 处理流发出的内容
  // ...
  completer.complete();
});

await completer.future;

controller.add('test content');

import 'package:flutter_test/flutter_test.dart';
import 'package:rxdart/rxdart.dart';
import 'package:async/async.dart';

void main() {
  testWidgets('test stream emits any content within time interval', (WidgetTester tester) async {
    final controller = StreamController<String>();
    final stream = controller.stream;
    final timeout = Timeout(Duration(seconds: 5));
    final observable = Observable(stream).takeWhile((_) => !timeout.hasExpired);
    final completer = Completer();

    observable.listen((data) {
      // 处理流发出的内容
      // ...
      completer.complete();
    });

    await completer.future;

    controller.add('test content');
  });
}