Fix a flaky test and work around issue 16003 in pkg/watcher.

pkg/watcher/test/utils.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 watcher.test.utils;
 
 import 'dart:async';
 import 'dart:collection';
 import 'dart:io';
 
@@ skipping 98 matching lines @@
 /// The stream of events from the watcher started with [startWatcher].
 ScheduledStream<WatchEvent> _watcherEvents;
 
 /// Creates a new [DirectoryWatcher] that watches a temporary directory and
 /// starts monitoring it for events.
 ///
 /// If [dir] is provided, watches a subdirectory in the sandbox with that name.
 void startWatcher({String dir}) {
   var testCase = currentTestCase.description;
   if (MacOSDirectoryWatcher.logDebugInfo) {
-    print("starting watcher for $testCase");
+    print("starting watcher for $testCase (${new DateTime.now()})");
   }
 
   // We want to wait until we're ready *after* we subscribe to the watcher's
   // events.
   _watcher = createWatcher(dir: dir, waitForReady: false);
 
   // Schedule [_watcher.events.listen] so that the watcher doesn't start
   // watching [dir] before it exists. Expose [_watcherEvents] immediately so
   // that it can be accessed synchronously after this.
   _watcherEvents = new ScheduledStream(futureStream(schedule(() {
     currentSchedule.onComplete.schedule(() {
       if (MacOSDirectoryWatcher.logDebugInfo) {
-        print("stopping watcher for $testCase");
+        print("stopping watcher for $testCase (${new DateTime.now()})");
       }
 
       _watcher = null;
       if (!_closePending) _watcherEvents.close();
 
       // If there are already errors, don't add this to the output and make
       // people think it might be the root cause.
       if (currentSchedule.errors.isEmpty) {
         _watcherEvents.expect(isDone);
       }
@@ skipping 148 matching lines @@
 
   schedule(() {
     var fullPath = p.join(_sandboxDir, path);
 
     // Create any needed subdirectories.
     var dir = new Directory(p.dirname(fullPath));
     if (!dir.existsSync()) {
       dir.createSync(recursive: true);
     }
 
+    if (MacOSDirectoryWatcher.logDebugInfo) {
+      print("[test] writing file $path");
+    }
     new File(fullPath).writeAsStringSync(contents);
 
     // Manually update the mock modification time for the file.
     if (updateModified) {
       // Make sure we always use the same separator on Windows.
       path = p.normalize(path);
 
       var milliseconds = _mockFileModificationTimes.putIfAbsent(path, () => 0);
       _mockFileModificationTimes[path]++;
     }
   }, "write file $path");
 }
 
 /// Schedules deleting a file in the sandbox at [path].
 void deleteFile(String path) {
   schedule(() {
+    if (MacOSDirectoryWatcher.logDebugInfo) {
+      print("[test] deleting file $path");
+    }
     new File(p.join(_sandboxDir, path)).deleteSync();
   }, "delete file $path");
 }
 
 /// Schedules renaming a file in the sandbox from [from] to [to].
 ///
 /// If [contents] is omitted, creates an empty file.
 void renameFile(String from, String to) {
   schedule(() {
+    if (MacOSDirectoryWatcher.logDebugInfo) {
+      print("[test] renaming file $from to $to");
+    }
+
     new File(p.join(_sandboxDir, from)).renameSync(p.join(_sandboxDir, to));
 
     // Make sure we always use the same separator on Windows.
     to = p.normalize(to);
 
     // Manually update the mock modification time for the file.
     var milliseconds = _mockFileModificationTimes.putIfAbsent(to, () => 0);
     _mockFileModificationTimes[to]++;
   }, "rename file $from to $to");
 }
 
 /// Schedules creating a directory in the sandbox at [path].
 void createDir(String path) {
   schedule(() {
+    if (MacOSDirectoryWatcher.logDebugInfo) {
+      print("[test] creating directory $path");
+    }
     new Directory(p.join(_sandboxDir, path)).createSync();
   }, "create directory $path");
 }
 
 /// Schedules renaming a directory in the sandbox from [from] to [to].
 void renameDir(String from, String to) {
   schedule(() {
+    if (MacOSDirectoryWatcher.logDebugInfo) {
+      print("[test] renaming directory $from to $to");
+    }
     new Directory(p.join(_sandboxDir, from))
         .renameSync(p.join(_sandboxDir, to));
   }, "rename directory $from to $to");
 }
 
 /// Schedules deleting a directory in the sandbox at [path].
 void deleteDir(String path) {
   schedule(() {
+    if (MacOSDirectoryWatcher.logDebugInfo) {
+      print("[test] deleting directory $path");
+    }
     new Directory(p.join(_sandboxDir, path)).deleteSync(recursive: true);
   }, "delete directory $path");
 }
 
 /// Runs [callback] with every permutation of non-negative [i], [j], and [k]
 /// less than [limit].
 ///
 /// Returns a set of all values returns by [callback].
 ///
 /// [limit] defaults to 3.
 Set withPermutations(callback(int i, int j, int k), {int limit}) {
   if (limit == null) limit = 3;
   var results = new Set();
   for (var i = 0; i < limit; i++) {
     for (var j = 0; j < limit; j++) {
       for (var k = 0; k < limit; k++) {
         results.add(callback(i, j, k));
       }
     }
   }
   return results;
 }