add test for polymer custom events

pkg/polymer/test/custom_event_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.web.custom_event_test;
+
+import 'dart:async';
+import 'dart:html';
+import 'package:polymer/polymer.dart';
+import 'package:unittest/unittest.dart';
+import 'package:unittest/html_config.dart';
+
+
+@CustomTag('foo-bar')
+class FooBar extends PolymerElement {
+  // A little too much boilerplate?
+  static const EventStreamProvider<CustomEvent> fooEvent =
+      const EventStreamProvider<CustomEvent>('foo');
+  static const EventStreamProvider<CustomEvent> barBazEvent =
+      const EventStreamProvider<CustomEvent>('barbaz');
+
+  FooBar.created() : super.created();
+
+  Stream<CustomEvent> get onFooEvent =>
+      FooBar.fooEvent.forTarget(this);
+  Stream<CustomEvent> get onBarBazEvent =>
+      FooBar.barBazEvent.forTarget(this);
+
+  fireFoo(x) => dispatchEvent(new CustomEvent('foo', detail: x));
+  fireBarBaz(x) => dispatchEvent(new CustomEvent('barbaz', detail: x));
+}
+
+@CustomTag('test-custom-event')
+class TestCustomEvent extends PolymerElement {
+  TestCustomEvent.created() : super.created();
+
+  get fooBar => getShadowRoot('test-custom-event').query('foo-bar').xtag;
+
+  final events = [];
+  fooHandler(e) => events.add(['foo', e]);
+  barBazHandler(e) => events.add(['barbaz', e]);
+}
+
+main() {
+  initPolymer();
+  useHtmlConfiguration();
+
+  setUp(() => Polymer.onReady);
+
+  test('custom event', () {
+    final testComp = query('test-custom-event');
+    final fooBar = testComp.fooBar;
+    fooBar.fireFoo(123);
+    fooBar.fireBarBaz(42);
+    fooBar.fireFoo(777);
+
+    final events = testComp.events;
+    expect(events.length, 3);
+    expect(events.map((e) => e[0]), ['foo', 'barbaz', 'foo']);
+    expect(events.map((e) => e[1].detail), [123, 42, 777]);
+  });
+}