Wrapping leaf nodes in non polymer elements

runtime/observatory/tests/observatory_ui/nav/notify_exception/connection_exception_test.dart

Index: runtime/observatory/tests/observatory_ui/nav/notify_exception/connection_exception_test.dart
diff --git a/runtime/observatory/tests/observatory_ui/nav/notify_exception/connection_exception_test.dart b/runtime/observatory/tests/observatory_ui/nav/notify_exception/connection_exception_test.dart
new file mode 100644
index 0000000000000000000000000000000000000000..8f518135811bc43a9958497b223300deb449607e
--- /dev/null
+++ b/runtime/observatory/tests/observatory_ui/nav/notify_exception/connection_exception_test.dart
@@ -0,0 +1,29 @@
+// 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/models.dart';
+import 'package:observatory/mocks.dart';
+import 'package:observatory/src/elements/nav/notify_exception.dart';
+
+main() {
+  NavNotifyExceptionElement.tag.ensureRegistration();
+
+  final ConnectionException exception = new ConnectionExceptionMock('message');
+  test('instantiation', () {
+    final NavNotifyExceptionElement e =
+                                new NavNotifyExceptionElement(exception);
+    expect(e, isNotNull, reason: 'element correctly created');
+  });
+  test('elements created after attachment', () async {
+    final NavNotifyExceptionElement e =
+                                new NavNotifyExceptionElement(exception);
+    document.body.append(e);
+    await e.onRendered.first;
+    expect(e.children.length, isNonZero, reason: 'has elements');
+    e.remove();
+    await e.onRendered.first;
+    expect(e.children.length, isZero, reason: 'is empty');
+  });
+}