tests/lib/async/zone_fork_test.dart

// Copyright (c) 2013, 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';

main() {
  Completer done = new Completer();
  List events = [];

  Expect.identical(Zone.root, Zone.current);
  Zone forked;
  forked = Zone.current.fork(
    specification: new ZoneSpecification(
      fork:
          (
            Zone self,
            ZoneDelegate parent,
            Zone origin,
            ZoneSpecification? zoneSpecification,
            Map<Object?, Object?>? mapValues,
          ) {
            // The zone is still the same as when origin.run was invoked, which
            // is the root zone. (The origin zone hasn't been set yet).
            Expect.identical(Zone.root, Zone.current);
            events.add("forked.fork");
            var descriptionRun = zoneSpecification!.run!;
            ZoneSpecification modified = new ZoneSpecification.from(
              zoneSpecification,
              run: <R>(self, parent, origin, R f()) {
                events.add("wrapped run");
                return descriptionRun(self, parent, origin, () {
                  events.add("wrapped f");
                  return f();
                });
              },
            );
            return parent.fork(origin, modified, mapValues);
          },
    ),
  );

  events.add("start");
  Zone forkedChild = forked.fork(
    specification: new ZoneSpecification(
      run: <R>(Zone self, ZoneDelegate parent, Zone origin, R f()) {
        events.add("executing child run");
        return parent.run(origin, f);
      },
    ),
  );

  events.add("after child fork");
  Expect.identical(Zone.root, Zone.current);

  forkedChild.run(() {
    events.add("child run");
  });

  events.add("after child run");

  Expect.listEquals([
    "start",
    "forked.fork",
    "after child fork",
    "wrapped run",
    "executing child run",
    "wrapped f",
    "child run",
    "after child run",
  ], events);
}