Wrapping leaf nodes in non polymer elements

runtime/observatory/tests/observatory_ui/error_ref_test.dart

+// Copyright (c) 2016, 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:observatory/repositories.dart';
+import 'package:observatory/src/elements/error_ref.dart';
+
+import 'helpers/webcomponents.dart';
+
+main() async{
+  await loadWebComponents();
+  ErrorRefElement.tag.ensureRegistration();
+
+  final ErrorRefMock ref = new ErrorRefMock(id: 'id', message: 'fixed-error-m');
+  test('instantiation', () {
+    final ErrorRefElement e = new ErrorRefElement(ref);
+    expect(e, isNotNull, reason: 'element correctly created');
+    expect(e.error, equals(ref));
+  });
+  group('elements', () {
+    test('created after attachment', () {
+      final ErrorRefElement e = new ErrorRefElement(ref);
+      expect(e.children.length, isZero,
+        reason: 'is empty');
+      document.body.append(e);
+      expect(e.children.length, isNonZero,
+        reason: 'has elements');
+      expect(e.innerHtml.contains(ref.message), isTrue,
+        reason: 'no message in the component');
+      e.remove();
+    });
+  });
+}