Migrated test block 167 to Dart 2.0.

tests/lib_strong/async/catch_errors21_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:async_helper/async_helper.dart';
-import "package:expect/expect.dart";
-import 'dart:async';
-import 'catch_errors.dart';
-
-main() {
-  asyncStart();
-  Completer done = new Completer();
-
-  var events = [];
-  var controller = new StreamController();
-  // Test that stream errors, as a result of bad user-code (`map`) are correctly
-  // caught by `catchErrors`. Note that the values are added outside both
-  // `catchErrors`, but since the `listen` happens in the most nested
-  // `catchErrors` it is caught there.
-  catchErrors(() {
-    catchErrors(() {
-      controller.stream.map((x) {
-        throw x;
-      }).listen((x) {
-        // Should not happen.
-        events.add("bad: $x");
-      });
-    }).listen((x) {
-      events.add("caught: $x");
-      if (x == 4) done.complete(true);
-    }, onDone: () {
-      Expect.fail("Unexpected callback");
-    });
-  }).listen((x) {
-    events.add("outer: $x");
-  }, onDone: () {
-    Expect.fail("Unexpected callback");
-  });
-
-  done.future.whenComplete(() {
-    // Give handlers time to run.
-    Timer.run(() {
-      Expect.listEquals([
-        "caught: 1",
-        "caught: 2",
-        "caught: 3",
-        "caught: 4",
-      ], events);
-      asyncEnd();
-    });
-  });
-
-  [1, 2, 3, 4].forEach(controller.add);
-  controller.close();
-}