Migrated test block 170 to Dart 2.0.

tests/lib_2/async/multiple_timer_test.dart

+// Copyright (c) 2012, 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.
+
+library multiple_timer_test;
+
+import 'dart:async';
+import 'package:async_helper/async_helper.dart';
+import 'package:expect/expect.dart';
+
+const Duration TIMEOUT1 = const Duration(seconds: 1);
+const Duration TIMEOUT2 = const Duration(seconds: 2);
+const Duration TIMEOUT3 = const Duration(milliseconds: 500);
+const Duration TIMEOUT4 = const Duration(milliseconds: 1500);
+
+// The stopwatch is more precise than the Timer.
+// Some browsers (Firefox and IE so far) can trigger too early. So we add more
+// margin. We use identical(1, 1.0) as an easy way to know if the test is
+// compiled by dart2js.

[Bob Nystrom, 2017/08/23 21:40:28]

Nit: "compiled by dart2js" -> "running on the web".

+int get safetyMargin => identical(1, 1.0) ? 100 : 0;
+
+main() {
+  Stopwatch _stopwatch1 = new Stopwatch();
+  Stopwatch _stopwatch2 = new Stopwatch();
+  Stopwatch _stopwatch3 = new Stopwatch();
+  Stopwatch _stopwatch4 = new Stopwatch();
+  List<int> _order;
+  int _message;
+
+  void timeoutHandler1() {
+    Expect.isTrue((_stopwatch1.elapsedMilliseconds + safetyMargin) >=
+        TIMEOUT1.inMilliseconds);
+    Expect.equals(_order[_message], 0);
+    _message++;
+    asyncEnd();
+  }
+
+  void timeoutHandler2() {
+    Expect.isTrue((_stopwatch2.elapsedMilliseconds + safetyMargin) >=
+        TIMEOUT2.inMilliseconds);
+    Expect.equals(_order[_message], 1);
+    _message++;
+    asyncEnd();
+  }
+
+  void timeoutHandler3() {
+    Expect.isTrue((_stopwatch3.elapsedMilliseconds + safetyMargin) >=
+        TIMEOUT3.inMilliseconds);
+    Expect.equals(_order[_message], 2);
+    _message++;
+    asyncEnd();
+  }
+
+  void timeoutHandler4() {
+    Expect.isTrue((_stopwatch4.elapsedMilliseconds + safetyMargin) >=
+        TIMEOUT4.inMilliseconds);
+    Expect.equals(_order[_message], 3);
+    _message++;
+    asyncEnd();
+  }
+
+  _order = new List<int>(4);
+  _order[0] = 2;
+  _order[1] = 0;
+  _order[2] = 3;
+  _order[3] = 1;
+  _message = 0;
+
+  asyncStart();
+  _stopwatch1.start();
+  new Timer(TIMEOUT1, timeoutHandler1);
+  asyncStart();
+  _stopwatch2.start();
+  new Timer(TIMEOUT2, timeoutHandler2);
+  asyncStart();
+  _stopwatch3.start();
+  new Timer(TIMEOUT3, timeoutHandler3);
+  asyncStart();
+  _stopwatch4.start();
+  new Timer(TIMEOUT4, timeoutHandler4);
+}