How to wait scheduled future with flutter_test? - flutter

Question

My widget execute an asynchronous task and I want to check whether it is complete or not.
But it seems widget tester terminates the test before the task is executed. Whole code is here.
class MyHomePageState extends State<MyHomePage> {
#override
void initState() {
super.initState();
test();
}
Stream<int?> stream(Future<void> Function() worker) async* {
Stream<int?> work() async* {
await worker();
yield 3;
}
yield* work();
}
Future<void> sampleWorker() async {
throw Error();
}
Future<void> test() async {
print('start');
try {
await for (final v in stream(sampleWorker)) {
print(v);
}
print('point 1');
} catch (error, stack) {
print(stack);
}
print('done');
}
}
void main() {
testWidgets('Widget test', (WidgetTester tester) async {
// Build our app and trigger a frame.
await tester.pumpWidget(MyApp());
await tester.pumpAndSettle(const Duration(milliseconds: 1000));
});
test('Plain test', () async {
await MyHomePageState().test();
});
}
I want both tests print stack trace, but only 'Plain test' shows expected behavior. The following is the log.
start
✓ Widget test
start
#0 MyHomePageState.sampleWorker (package:bug_report/main.dart:48:5)
#1 MyHomePageState.stream.work (package:bug_report/main.dart:40:19)
<asynchronous suspension>
#2 StackZoneSpecification._registerUnaryCallback.<anonymous closure> (package:stack_trace/src/stack_zone_specification.dart)
<asynchronous suspension>
done
✓ Plain test
How to make first test prints stack trace? I should not await test() because it should be widget's internal task.

Answer 1

Try WidgetTester's runAsync function to await an arbitrary amount of time for an internal widget's async task to complete.