Fix regression in meta-serializing rules

pkg/serialization/test/serialization_test.dart

 // Copyright (c) 2012, 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.
 
 library serialization_test;
 
 import 'dart:json' as json;
 import 'package:unittest/unittest.dart';
 import 'package:serialization/serialization.dart';
 import 'package:serialization/src/serialization_helpers.dart';
@@ skipping 217 matching lines @@
     var list = w.states[1].first;
     expect(w.stateForReference(rootNode[children]), list);
     var parentNode = w.stateForReference(list[0])[parent];
     expect(w.stateForReference(parentNode), rootNode);
   });
 
   test('round-trip', () {
     runRoundTripTest(nodeSerializerReflective);
   });
 
+  test('round-trip with explicit self-description', () {
+    // We provide a setup function which, when run the second time,
+    // returns a blank serialization, to make sure it will fail
+    // the second time.
+    var s;
+    oneShotSetup(node) {
+      if (s == null) {
+        s = nodeSerializerReflective(node)..selfDescribing = true;
+        return s;
+      } else {
+        s = null;
+        return new Serialization.blank()
+            ..namedObjects['Node'] = reflect(new Node('')).type;;
+      }
+    }
+
+    runRoundTripTest(oneShotSetup);
+  });
+
   test('round-trip ClosureRule', () {
     runRoundTripTest(nodeSerializerNonReflective);
   });
 
   test('round-trip with essential parent', () {
     runRoundTripTest(nodeSerializerWithEssentialParent);
   });
 
   test('round-trip, flat format', () {
     runRoundTripTestFlat(nodeSerializerReflective);
@@ skipping 507 matching lines @@
   }
   findValue(String key, Map state) {
     var answer;
     for (var each in state.keys) {
       var value = state[each];
       if (value == key) return each;
     }
     return null;
   }
 }