New expectation functions plus convert old tests to use these.

samples/tests/samples/lib/observable/event_batch_tests.dart

 // Copyright (c) 2011, 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.
 
 testEventBatch() {
   test('EventBatch', () {
     // check that all events are fired at the end. Use all record methods
     // in abstract observable
     final target = new AbstractObservable();
     EventSummary res = null;
     target.addChangeListener((summary) {
-      expect(res).isNull();
+      expect(res, isNull());
       res = summary;
-      expect(res).isNotNull();
+      expect(res, isNotNull());
     });
 
     final f = EventBatch.wrap((e) {
       target.recordPropertyUpdate('pM', 10, 11);
       target.recordPropertyUpdate('pL', '11', '13');
       target.recordListUpdate(2, 'a', 'b');
       target.recordListInsert(5, 'a');
       target.recordListRemove(4, 'c');
       target.recordGlobalChange();
     });
 
-    expect(res).isNull();
+    expect(res, isNull());
     f(null);
-    expect(res).isNotNull();
+    expect(res, isNotNull());
 
-    expect(res.events.length).equals(6);
+    expect(res.events, hasLength(6));
     validateUpdate(res.events[0], target, 'pM', null, 10, 11);
     validateUpdate(res.events[1], target, 'pL', null, '11', '13');
     validateUpdate(res.events[2], target, null, 2, 'a', 'b');
     validateInsert(res.events[3], target, null, 5, 'a');
     validateRemove(res.events[4], target, null, 4, 'c');
     validateGlobal(res.events[5], target);
   });
 }