fix nested bindings in polymer_expressions

pkg/polymer/test/nested_binding_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.
+
+library polymer.test.nested_binding_test;
+
+import 'dart:async';
+import 'dart:html';
+import 'dart:mirrors';
+import 'package:polymer/polymer.dart';
+import 'package:unittest/unittest.dart';
+import 'package:unittest/html_config.dart';
+import 'package:unittest/matcher.dart';
+
+@CustomTag('my-test')
+class MyTest extends PolymerElement {
+  final List fruits = toObservable(['apples', 'oranges', 'pears']);
+
+  final _testDone = new Completer();
+
+  MyTest.created() : super.created();
+
+  _runTest(_) {
+    expect($['fruit'].text.trim(), 'Short name: [pears]');
+    _testDone.complete();
+  }
+
+  ready() {
+    onMutation($['fruit']).then(_runTest);
+  }
+
+}
+
+main() {
+  reflectClass(String); // so we can call string.length

[Siggi Cherem (dart-lang), 2013/11/01 01:54:33]

didn't know this was also a hint for dart2js. Is this expressible with
@MirrorsUsed ?

[Jennifer Messerly, 2013/11/01 02:14:56]

clarified comment. this line doesn't do anything, I'm just using mirrors so
editor doesn't complain :). it's the "import mirrors" up top that pulls in
String.length

+
+  initPolymer();
+  useHtmlConfiguration();
+
+  setUp(() => Polymer.onReady);
+
+  test('ready called', () =>
+      (query('my-test') as MyTest)._testDone.future as Future);

[Siggi Cherem (dart-lang), 2013/11/01 01:54:33]

remove as Future?

[Jennifer Messerly, 2013/11/01 02:14:56]

good catch :)

+}