Pub integration tests sometimes need more than 20 seconds.

dart/sdk/lib/_internal/pub/test/test_pub.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.
 
 /// Test infrastructure for testing pub. Unlike typical unit tests, most pub
 /// tests are integration tests that stage some stuff on the file system, run
 /// pub, and then validate the results. This library provides an API to build
 /// tests like that.
 library test_pub;
 
@@ skipping 21 matching lines @@
 import '../lib/src/system_cache.dart';
 import '../lib/src/utils.dart';
 import '../lib/src/validator.dart';
 import 'descriptor.dart' as d;
 
 /// This should be called at the top of a test file to set up an appropriate
 /// test configuration for the machine running the tests.
 initConfig() {
   useCompactVMConfiguration();
   filterStacks = true;
+  unittestConfiguration.timeout = const Duration(seconds: 60);

[kustermann, 2013/09/03 07:32:38]

That's not the best thing to do. If this test is really timing out, the result
of the test can sometimes be 'FAIL' (if this timer fires first) or 'TIMEOUT' (if
the timer of test.dart fires first).
(i.e. due to the fact that test.dart is also using a 60 second timeout).

There are two alternatives:
- making an opt-out solutions and using it here
- lowering the timeout to 30-45 seconds

A hackisch way of 'opt-out' would be:
  unittestConfiguration.timeout = const Duration(hours: 24)

 }
 
 /// Returns whether we're running on a Dart build bot.
 bool get runningOnBuildbot =>
   Platform.environment.containsKey('BUILDBOT_BUILDERNAME');
 
 /// The current [HttpServer] created using [serve].
 var _server;
 
 /// The list of paths that have been requested from the server since the last
@@ skipping 733 matching lines @@
   bool matches(item, Map matchState) {
     if (item is! Pair) return false;
     return _firstMatcher.matches(item.first, matchState) &&
         _lastMatcher.matches(item.last, matchState);
   }
 
   Description describe(Description description) {
     description.addAll("(", ", ", ")", [_firstMatcher, _lastMatcher]);
   }
 }