Port of github.com/polymer/polymer.

pkg/polymer/test/prop_attr_reflection_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 'dart:html';
+import 'package:unittest/unittest.dart';
+import 'package:unittest/html_config.dart';
+import 'package:polymer/platform.dart' as Platform;
+import 'package:polymer/polymer.dart';
+
+class XFoo extends PolymerElement {
+  @observable var foo = '';
+  @observable String baz = '';
+}
+
+class XBar extends XFoo {
+  @observable int zot = 3;
+  @observable bool zim = false;
+  @observable String str = 'str';
+  @observable Object obj;
+}
+
+class XCompose extends PolymerElement {
+  @observable bool zim = false;
+}
+
+main() {
+  useHtmlConfiguration();
+
+  // Most tests use @CustomTag, here we test out the impertive register:
+  Polymer.register('x-foo', XFoo);
+  Polymer.register('x-bar', XBar);
+  Polymer.register('x-compose', XCompose);
+
+  test('property attribute reflection', () {
+    var xcompose = query('x-compose').xtag;
+    var xfoo = query('x-foo').xtag;
+    xfoo.foo = 5;
+    Platform.flush();
+    Platform.endOfMicrotask(expectAsync0(() {

[blois, 2013/09/27 21:40:52]

Would be nice to have a Future version of endOfMicrotask, if even only for
tests. These expectAsync0's are always error-prone and I thought there was even
a drive to eliminate them from the test framework.

[Jennifer Messerly, 2013/09/30 17:44:37]

good point. I recall starting that refactoring but reverted for some reason I
can't recall. I'll give it another shot.

+      expect(xcompose.$['bar'].attributes.containsKey('zim'), false,
+          reason: 'attribute bound to property updates when binding is made');
+
+      expect('${xfoo.foo}', xfoo.attributes['foo'],
+          reason: 'attribute reflects property as string');
+      xfoo.attributes['foo'] = '27';
+      // TODO(jmesserly): why is JS leaving this as a String? From the code it
+      // looks like it should use the type of 5 and parse it as a number.
+      expect('${xfoo.foo}', xfoo.attributes['foo'],
+          reason: 'property reflects attribute');
+      //
+      xfoo.baz = 'Hello';
+      Platform.flush();
+      Platform.endOfMicrotask(expectAsync0(() {
+        expect(xfoo.baz, xfoo.attributes['baz'],
+            reason: 'attribute reflects property');
+        //
+        var xbar = query('x-bar').xtag;
+        //
+        xbar.foo = 'foo!';
+        xbar.zot = 27;
+        xbar.zim = true;
+        xbar.str = 'str!';
+        xbar.obj = {'hello': 'world'};
+        Platform.flush();
+        Platform.endOfMicrotask(expectAsync0(() {
+          expect(xbar.foo, xbar.attributes['foo'],
+              reason: 'inherited published property is reflected');
+          expect('${xbar.zot}', xbar.attributes['zot'],
+              reason: 'attribute reflects property as number');
+          expect(xbar.attributes['zim'], '', reason:
+              'attribute reflects true valued boolean property as '
+              'having attribute');
+          expect(xbar.str, xbar.attributes['str'],
+              reason: 'attribute reflects property as published string');
+          expect(xbar.attributes.containsKey('obj'), false,
+              reason: 'attribute does not reflect object property');
+          xbar.attributes['zim'] = 'false';
+          xbar.attributes['foo'] = 'foo!!';
+          xbar.attributes['zot'] = '54';
+          xbar.attributes['str'] = 'str!!';
+          xbar.attributes['obj'] = "{'hello': 'world'}";
+          expect(xbar.foo, xbar.attributes['foo'],
+              reason: 'property reflects attribute as string');
+          expect(xbar.zot, 54,
+              reason: 'property reflects attribute as number');
+          expect(xbar.zim, false,
+              reason: 'property reflects attribute as boolean');
+          expect(xbar.str, 'str!!',
+              reason: 'property reflects attribute as published string');
+          expect(xbar.obj, {'hello': 'world'},
+              reason: 'property reflects attribute as object');
+          xbar.zim = false;
+          Platform.flush();
+          Platform.endOfMicrotask(expectAsync0(() {
+            expect(xbar.attributes.containsKey('zim'), false, reason:
+                'attribute reflects false valued boolean property as NOT '
+                'having attribute');
+            var objAttr = xbar.attributes['obj'];
+            xbar.obj = 'hi';
+            Platform.endOfMicrotask(expectAsync0(() {
+              expect(xbar.attributes['obj'], objAttr, reason:
+                  'do not reflect property with default type of object');
+            }));
+          }));
+        }));
+      }));
+    }));
+  });
+}