Pump the event queue manually rather than using a timer.

pkg/scheduled_test/lib/src/utils.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.
 
 library utils;
 
 import 'dart:async';
 
 /// Configures [future] so that its result (success or exception) is passed on
 /// to [completer].
 void chainToCompleter(Future future, Completer completer) {
   future.then((value) => completer.complete(value),
       onError: (e) => completer.completeError(e.error, e.stackTrace));
 }
 
 /// Prepends each line in [text] with [prefix].
 String prefixLines(String text, {String prefix: '| '}) =>
   text.split('\n').map((line) => '$prefix$line').join('\n');
-
-/// Returns a [Future] that completes in at least [milliseconds].
-///
-/// This pumps the event loop after every millisecond of sleeping. This should
-/// ensure that even if the CPU is pegged and code is running much slower than
-/// expected, the sleep will take longer than any non-sleep code that's running.
-Future sleep(int milliseconds) {
-  if (milliseconds == 0) return new Future.immediate(null);
-  return _sleep1().then((_) => sleep(milliseconds - 1));
-}
-
-/// Returns a [Future] that completes in one millisecond.
-Future _sleep1() {
-  var completer = new Completer();
-  new Timer(1, (_) => completer.complete());
-  return completer.future;
-}
-
-/// Wraps [input] to provide a timeout. If [input] completes before
-/// [milliseconds] have passed, then the return value completes in the same way.
-/// However, if [milliseconds] pass before [input] has completed, [onTimeout] is
-/// run and its result is passed to [input] (with chaining, if it returns a
-/// [Future]).
-///
-/// Note that timing out will not cancel the asynchronous operation behind
-/// [input].
-Future timeout(Future input, int milliseconds, onTimeout()) {
-  bool completed = false;
-  var completer = new Completer();
-  var timer = new Timer(milliseconds, (_) {
-    completed = true;
-    chainToCompleter(new Future.immediate(null).then((_) => onTimeout()),
-        completer);
-  });
-  input.then((value) {
-    if (completed) return;
-    timer.cancel();
-    completer.complete(value);
-  }).catchError((e) {
-    if (completed) return;
-    timer.cancel();
-    completer.completeError(e.error, e.stackTrace);
-  });
-  return completer.future;
-}