port polymer data binding tests

pkg/polymer/test/unbind_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:async' show Future;
+import 'dart:html';
+import 'dart:mirrors' show reflect, reflectClass, MirrorSystem;
+import 'package:custom_element/custom_element.dart' show createElement;
+import 'package:observe/src/microtask.dart' show performMicrotaskCheckpoint;
+import 'package:polymer/polymer.dart';
+import 'package:polymer/platform.dart' as Platform;
+import 'package:unittest/unittest.dart';
+import 'package:unittest/html_config.dart';
+
+@CustomTag('x-test')
+class XTest extends PolymerElement {
+  @observable var foo = '';
+  @observable var bar;
+
+  bool forceReady = true;
+  bool fooWasChanged = false;
+  var validBar;
+
+  ready() {}
+
+  fooChanged() {
+    fooWasChanged = true;
+  }
+
+  barChanged() {
+    validBar = bar;
+  }
+
+  bool get isBarValid => validBar == bar;
+}
+
+main() {
+  useHtmlConfiguration();
+
+  test('unbind', unbindTests);
+}
+
+Future testAsync(List<Function> tests, int delayMs, [List args]) {
+  if (tests.length == 0) return new Future.value();
+  // TODO(jmesserly): CustomElements.takeRecords();
+  return new Future.delayed(new Duration(milliseconds: delayMs), () {
+    if (args == null) args = [];
+    var lastArgs = Function.apply(tests.removeAt(0), args);
+    return testAsync(tests, delayMs, lastArgs);
+  });
+}
+
+unbindTests() {
+
+  var xTest = document.query('x-test').xtag;
+  xTest.foo = 'bar';
+  Platform.flush();
+
+  // TODO(jmesserly): fix this when it's easier to get a private symbol.
+  final unboundSymbol = reflectClass(PolymerElement).variables.keys
+      .firstWhere((s) => MirrorSystem.getName(s) == '_unbound');
+
+  _unbound(node) => reflect(node).getField(unboundSymbol).reflectee;
+
+  return testAsync([
+    () {
+      expect(_unbound(xTest), null, reason:
+          'element is bound when inserted');
+      expect(xTest.fooWasChanged, true, reason:
+          'element is actually bound');
+      xTest.remove();
+    },

[Siggi Cherem (dart-lang), 2013/10/04 21:13:46]

totally optional, but since every callback takes a single argument, it might be
fine to do each delay here and forward results:

  return delay(null)
      .then((_) { expect ... xTest.remove(); })
      .then(delay)
      .then((_) { ... return createElement('x-test').xtag; })
      .then(delay)
      .then((node) { ... return node; })
      ...


where delay is:

Future delay(arg) =>
  new Future.deplayed(new Duration(milliseconds: ms).then((_) => arg);


But I'm totally fine keeping it how it is if you think it's not worth it.

+    () {
+      expect(_unbound(xTest), true, reason:
+          'element is unbound when removed');
+      return [createElement('x-test').xtag];
+    },
+    (node) {
+      expect(_unbound(node), null, reason:
+          'element is bound when not inserted');
+      node.foo = 'bar';
+      Platform.flush();
+      return [node];
+    },
+    (node) {
+      expect(node.fooWasChanged, true, reason: 'node is actually bound');
+      var n = createElement('x-test').xtag;
+      n.cancelUnbindAll();
+      return [n];
+    },
+    (node) {
+      expect(_unbound(node), null, reason:
+          'element is bound when cancelUnbindAll is called');
+      node.unbindAll();
+      expect(_unbound(node), true, reason:
+          'element is unbound when unbindAll is called');
+      var n = createElement('x-test')..id = 'foobar!!!';
+      document.body.append(n);
+      // TODO(jmesserly): this is used to force the CustomElement polyfill to
+      // recognize the inserted node.
+      performMicrotaskCheckpoint();
+      return [n.xtag];
+    },
+    (node) {
+      expect(_unbound(node), null, reason:
+          'element is bound when manually inserted');
+      node.remove();
+      return [node];
+    },
+    (node) {
+      expect(_unbound(node), true, reason:
+          'element is unbound when manually removed is called');
+    }
+    // TODO(sorvell): In IE, the unbind time is indeterminate, so wait an
+    // extra beat.
+  ], 50);
+}