Ensure that AnalysisContext futures are completed when context disposed.

pkg/analysis_server/test/analysis_server_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 test.analysis_server;
 
 import 'dart:async';
 
 import 'package:analysis_server/src/analysis_server.dart';
 import 'package:analysis_server/src/constants.dart';
@@ skipping 30 matching lines @@
         channel,
         resourceProvider,
         new MockPackageMapProvider(),
         null,
         new AnalysisServerOptions(),
         new MockSdk(),
         InstrumentationService.NULL_SERVICE,
         rethrowExceptions: true);
   }
 
+  Future test_contextDisposed() {
+    resourceProvider.newFolder('/foo');
+    resourceProvider.newFile('/foo/bar.dart', 'library lib;');
+    server.setAnalysisRoots('0', ['/foo'], [], {});
+    AnalysisContext context;
+    return pumpEventQueue().then((_) {
+      context = server.getAnalysisContext('/foo/bar.dart');
+      server.setAnalysisRoots('1', [], [], {});
+    }).then((_) => pumpEventQueue()).then((_) {
+      expect(context.isDisposed, isTrue);
+    });
+  }
+
   Future test_contextsChangedEvent() {
     resourceProvider.newFolder('/foo');
 
     bool wasAdded = false;
     bool wasChanged = false;
     bool wasRemoved = false;
     server.onContextsChanged.listen((ContextsChangedEvent event) {
       wasAdded = event.added.length == 1;
       if (wasAdded) {
         expect(event.added[0], isNotNull);
@@ skipping 154 matching lines @@
   @override
   Response handleRequest(Request request) {
     if (request.method == 'echo') {
       return new Response(request.id, result: {
         'echo': true
       });
     }
     return null;
   }
 }