Add debugging prints to the Mac OS directory watcher.

pkg/watcher/test/utils.dart

Index: pkg/watcher/test/utils.dart
diff --git a/pkg/watcher/test/utils.dart b/pkg/watcher/test/utils.dart
index 567bdb22102cf455d0fd43fa81ec94dfac1bea86..a7bd9b636234ba849a44155b07f6ff62a9f75a6a 100644
--- a/pkg/watcher/test/utils.dart
+++ b/pkg/watcher/test/utils.dart
@@ -15,6 +15,9 @@ import 'package:watcher/watcher.dart';
 import 'package:watcher/src/stat.dart';
 import 'package:watcher/src/utils.dart';
 
+// TODO(nweiz): remove this when issue 15042 is fixed.
+import 'package:watcher/src/directory_watcher/mac_os.dart';
+
 /// The path to the temporary sandbox created for each test. All file
 /// operations are implicitly relative to this directory.
 String _sandboxDir;
@@ -115,6 +118,11 @@ Stream _watcherEvents;
 ///
 /// 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");
+  }
+
   // We want to wait until we're ready *after* we subscribe to the watcher's
   // events.
   _watcher = createWatcher(dir: dir, waitForReady: false);
@@ -128,6 +136,10 @@ void startWatcher({String dir}) {
         onError: currentSchedule.signalError);
 
     currentSchedule.onComplete.schedule(() {
+      if (MacOSDirectoryWatcher.logDebugInfo) {
+        print("stopping watcher for $testCase");
+      }
+
       var numEvents = _nextEvent;
       subscription.cancel();
       _nextEvent = 0;