Make sure Observatory tests run for each commit. Fix broken tests.

runtime/observatory/test/contexts_test.dart

 // Copyright (c) 2014, 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 inbound_references_test;
 
 import 'package:observatory/service_io.dart';
 import 'package:unittest/unittest.dart';
 import 'test_helper.dart';
 
@@ skipping 54 matching lines @@
 (Isolate isolate) =>
   isolate.rootLib.load().then((Library lib) {
     Field field = lib.variables.singleWhere((v) => v.name == 'copyingBlock');
     return field.value.load().then((Instance block) {
       expect(block.isClosure, isTrue);
       expect(block.closureCtxt.isContext, isTrue);
       expect(block.closureCtxt.length, equals(1));
       return block.closureCtxt.load().then((Context ctxt) {
         expect(ctxt.variables.single['value'].isString, isTrue);
         expect(ctxt.variables.single['value'].valueAsString, equals('I could be copied into the block'));
-        expect(block.closureCtxt.parentContext.isNull, isTrue);
+        expect(ctxt.parentContext.isContext, isTrue);
+        expect(ctxt.parentContext.length, equals(0));
+        return ctxt.parentContext.load().then((Context outerCtxt) {
+          expect(outerCtxt.parentContext.isNull, isTrue);
+        });
       });
     });
   }),
 
 (Isolate isolate) =>
   isolate.rootLib.load().then((Library lib) {
     Field field = lib.variables.singleWhere((v) => v.name == 'fullBlock');
     return field.value.load().then((Instance block) {
       expect(block.isClosure, isTrue);
       expect(block.closureCtxt.isContext, isTrue);
       expect(block.closureCtxt.length, equals(1));
       return block.closureCtxt.load().then((ctxt) {
         expect(ctxt.variables.single['value'].isInt, isTrue);
         expect(ctxt.variables.single['value'].valueAsString, equals('43'));
-        expect(ctxt.parentContext.isNull, isTrue);
+        expect(ctxt.parentContext.isContext, isTrue);
+        expect(ctxt.parentContext.length, equals(0));
+        return ctxt.parentContext.load().then((Context outerCtxt) {
+          expect(outerCtxt.parentContext.isNull, isTrue);
+        });
       });
     });
   }),
 
 (Isolate isolate) =>
   isolate.rootLib.load().then((Library lib) {
     Field field = lib.variables.singleWhere((v) => v.name == 'fullBlockWithChain');
     return field.value.load().then((Instance block) {
       expect(block.isClosure, isTrue);
       expect(block.closureCtxt.isContext, isTrue);
       expect(block.closureCtxt.length, equals(1));
       return block.closureCtxt.load().then((Context ctxt) {
         expect(ctxt.variables.single['value'].isInt, isTrue);
         expect(ctxt.variables.single['value'].valueAsString, equals('4201'));
         expect(ctxt.parentContext.isContext, isTrue);
         expect(ctxt.parentContext.length, equals(1));
         return ctxt.parentContext.load().then((Context outerCtxt) {
           expect(outerCtxt.variables.single['value'].isInt, isTrue);
           expect(outerCtxt.variables.single['value'].valueAsString, equals('421'));
-          expect(outerCtxt.parentContext.isNull, isTrue);
+          expect(outerCtxt.parentContext.isContext, isTrue);
+          expect(outerCtxt.parentContext.length, equals(0));
+          return outerCtxt.parentContext.load().then((Context outerCtxt2) {
+            expect(outerCtxt2.parentContext.isNull, isTrue);
+          });
         });
       });
     });
   }),
 
 ];
 
 main(args) => runIsolateTests(args, tests, testeeBefore: script);