sdk/tests/lib/async/uncaught_error_handler_throws_test.dart

// Copyright (c) 2021, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

import 'package:expect/async_helper.dart';
import 'package:expect/expect.dart';
import 'dart:async';

void main() async {
  asyncStart();
  await testThrowSame();
  await testThrowOther();
  asyncEnd();
}

Future<void> testThrowSame() async {
  asyncStart();
  var object1 = Object();
  var stack1 = StackTrace.current;
  var outerZone = Zone.current;
  var firstZone = Zone.current.fork(
    specification: onError((error, stack) {
      // Uncaught error handlers run in the parent zone.
      Expect.identical(outerZone, Zone.current);
      Expect.identical(object1, error);
      Expect.identical(stack1, stack); // Get same stack trace.
      asyncEnd();
    }),
  );
  firstZone.run(() async {
    Expect.identical(firstZone, Zone.current);
    var secondZone = Zone.current.fork(
      specification: onError((error, stack) {
        // Uncaught error handlers run in the parent zone.
        Expect.identical(firstZone, Zone.current);
        Expect.identical(object1, error);
        Expect.identical(stack1, stack);
        throw error; // Throw same object
      }),
    );
    secondZone.run(() async {
      Expect.identical(secondZone, Zone.current);
      Future.error(object1, stack1); // Unhandled async error.
      await Future(() {});
    });
  });
}

Future<void> testThrowOther() async {
  asyncStart();
  var object1 = Object();
  var object2 = Object();
  var stack1 = StackTrace.current;
  var outerZone = Zone.current;
  var firstZone = Zone.current.fork(
    specification: onError((error, stack) {
      Expect.identical(outerZone, Zone.current);
      Expect.identical(object2, error);
      Expect.notIdentical(stack1, stack); // Get different stack trace.
      asyncEnd();
    }),
  );
  firstZone.run(() async {
    Expect.identical(firstZone, Zone.current);
    var secondZone = Zone.current.fork(
      specification: onError((error, stack) {
        Expect.identical(firstZone, Zone.current);
        Expect.identical(object1, error);
        Expect.identical(stack1, stack);
        throw object2; // Throw different object
      }),
    );
    secondZone.run(() async {
      Expect.identical(secondZone, Zone.current);
      Future.error(object1, stack1); // Unhandled async error.
      await Future(() {});
    });
  });
}

ZoneSpecification onError(void Function(Object, StackTrace) handler) {
  return ZoneSpecification(
    handleUncaughtError: (s, p, z, e, st) => handler(e, st),
  );
}