Migrate async tests to strong

tests/lib_strong/async/future_value_chain2_test.dart

Index: tests/lib_strong/async/future_value_chain2_test.dart
diff --git a/tests/lib_strong/async/future_value_chain2_test.dart b/tests/lib_strong/async/future_value_chain2_test.dart
new file mode 100644
index 0000000000000000000000000000000000000000..3b31c3df3b32ce03410a96a4fb3976a9de3d5c28
--- /dev/null
+++ b/tests/lib_strong/async/future_value_chain2_test.dart
@@ -0,0 +1,20 @@
+// 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 'package:async_helper/async_helper.dart';
+import "package:expect/expect.dart";
+import 'dart:async';
+
+
+main() {
+  asyncStart();
+  var errorFuture = new Future.error(499);
+  var valueChainFuture = new Future.sync(() => errorFuture);
+  // The errorFuture must not be propagated immediately as we would otherwise
+  // not have time to catch the error.
+  valueChainFuture.catchError((error) {
+    Expect.equals(499, error);
+    asyncEnd();
+  });
+}