first cut simple code completion results

pkg/analysis_server/test/mocks.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 mocks;
 
 import 'dart:async';
 import 'dart:io';
 
 @MirrorsUsed(targets: 'mocks', override: '*')
@@ skipping 227 matching lines @@
 
   @override
   Description describe(Description description) {
     return description.addDescriptionOf(
         'response with identifier "$_id" and without error');
   }
 
   @override
   bool matches(item, Map matchState) {
     Response response = item;
-    return response.id == _id && response.error == null;
+    return response != null && response.id == _id && response.error == null;
   }
 
   @override
   Description describeMismatch(item, Description mismatchDescription,
                                Map matchState, bool verbose) {
     Response response = item;
-    var id = response.id;
-    RequestError error = response.error;
-    mismatchDescription.add('has identifier "$id"');
-    if (error != null) {
-      mismatchDescription.add(' and has error $error');
+    if (response == null) {
+      mismatchDescription.add('is null response');
+    } else {
+      var id = response.id;
+      RequestError error = response.error;
+      mismatchDescription.add('has identifier "$id"');
+      if (error != null) {
+        mismatchDescription.add(' and has error $error');
+      }
     }
     return mismatchDescription;
   }
 }
 
 
 /**
  * A [Matcher] that check that the given [Response] has an expected identifier
  * and has an error.
  */
@@ skipping 46 matching lines @@
   /**
    * Dependency list that will be returned by the next call to [computePackageMap].
    */
   Set<String> dependencies = new Set<String>();
 
   @override
   PackageMapInfo computePackageMap(resource.Folder folder) {
     return new PackageMapInfo(packageMap, dependencies);
   }
 }