Fix a typo in path_set_test.

pkg/watcher/test/path_set_test.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.
 
 import 'package:path/path.dart' as p;
 import 'package:unittest/unittest.dart';
 import 'package:watcher/src/path_set.dart';
 
 import 'utils.dart';
 
@@ skipping 200 matching lines @@
         "root/path/to/one",
         "root/path/to/two",
       ].map(p.normalize)));
     });
 
     test("doesn't return paths removed from the set", () {
       set.add("root/path/to/one");
       set.add("root/path/to/two");
       set.remove("root/path/to/two");
 
-      expect(set.toSet(), unorderedEquals([p.normalizze("root/path/to/one")]));
+      expect(set.toSet(), unorderedEquals([p.normalize("root/path/to/one")]));
     });
   });
 
   group("clear", () {
     test("removes all paths from the set", () {
       set.add("root/path");
       set.add("root/path/to/one");
       set.add("root/path/to/two");
 
       set.clear();
       expect(set.toSet(), isEmpty);
     });
   });
 }