Use the polling watcher by default in pub tests for now.

sdk/lib/_internal/pub/lib/src/barback.dart

Index: sdk/lib/_internal/pub/lib/src/barback.dart
diff --git a/sdk/lib/_internal/pub/lib/src/barback.dart b/sdk/lib/_internal/pub/lib/src/barback.dart
index 7e317f63ecccb05af3aa98d1b09df49c5744a79e..e2f32bacfd1bb57f19053ddae88b0d81eb039533 100644
--- a/sdk/lib/_internal/pub/lib/src/barback.dart
+++ b/sdk/lib/_internal/pub/lib/src/barback.dart
@@ -8,6 +8,7 @@ import 'dart:async';
 
 import 'package:barback/barback.dart';
 import 'package:path/path.dart' as path;
+import 'package:watcher/watcher.dart';
 
 import 'barback/load_all_transformers.dart';
 import 'barback/pub_package_provider.dart';
@@ -108,7 +109,7 @@ class TransformerId {
 /// the app when the server is started will be maintained.
 Future<BarbackServer> createServer(String host, int port, PackageGraph graph,
     BarbackMode mode, {Iterable<Transformer> builtInTransformers,
-    bool watchForUpdates: true}) {
+    WatcherType watcher: WatcherType.AUTO}) {
   var provider = new PubPackageProvider(graph);
   var barback = new Barback(provider);
 
@@ -117,8 +118,15 @@ Future<BarbackServer> createServer(String host, int port, PackageGraph graph,
   return BarbackServer.bind(host, port, barback, graph.entrypoint.root.name)
       .then((server) {
     return new Future.sync(() {
-      if (watchForUpdates) return watchSources(graph, barback);
-      loadSources(graph, barback);
+      if (watcher == WatcherType.NONE) {
+        loadSources(graph, barback);
+        return;
+      }
+
+      return watchSources(graph, barback, (directory) {
+        if (watcher == WatcherType.AUTO) return new DirectoryWatcher(directory);
+        return new PollingDirectoryWatcher(directory);

[Bob Nystrom, 2013/11/08 01:32:32]

How about making this a factory method on WatcherType itself?

[nweiz, 2013/11/08 01:44:24]

Done.

+      });
     }).then((_) {
       var completer = new Completer();
 
@@ -155,6 +163,20 @@ Future<BarbackServer> createServer(String host, int port, PackageGraph graph,
   });
 }
 
+class WatcherType {
+  static const AUTO = const WatcherType._("auto");
+
+  static const POLLING = const WatcherType._("polling");
+
+  static const NONE = const WatcherType._("none");
+
+  final String _name;
+
+  const WatcherType._(this._name);
+
+  String toString() => _name;
+}
+
 /// Converts [id] to a "package:" URI.
 ///
 /// This will throw an [ArgumentError] if [id] doesn't represent a library in