Refactor Source.

sdk/lib/_internal/pub/test/lock_file_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 lock_file_test;
 
+import 'dart:async';
+
 import 'package:unittest/unittest.dart';
 import 'package:yaml/yaml.dart';
 
 import '../lib/src/lock_file.dart';
 import '../lib/src/package.dart';
+import '../lib/src/pubspec.dart';
 import '../lib/src/source.dart';
 import '../lib/src/source_registry.dart';
 import '../lib/src/version.dart';
 import 'test_pub.dart';
 
 class MockSource extends Source {
   final String name = 'mock';
-  final bool shouldCache = false;
+
+  Future<Pubspec> onDescribe(PackageId id) => throw new UnsupportedError(
+      "Cannot describe mock packages.");
+
+  Future<bool> get(PackageId id, String path) => throw new UnsupportedError(
+      "Cannot get a mock package.");
+
+  Future<String> getDirectory(PackageId id) => throw new UnsupportedError(
+      "Cannot get the directory for mock packages.");
 
   dynamic parseDescription(String filePath, String description,
                            {bool fromLockFile: false}) {
     if (!description.endsWith(' desc')) throw new FormatException();
     return description;
   }
 
+  bool descriptionsEqual(description1, description2) =>
+      description1 == description2;
+
   String packageName(String description) {
     // Strip off ' desc'.
     return description.substring(0, description.length - 5);
   }
 }
 
 main() {
   initConfig();
 
   var sources = new SourceRegistry();
@@ skipping 153 matching lines @@
               'version': '3.2.1',
               'source': 'mock',
               'description': 'bar desc'
             }
           }
         }));
       });
     });
   });
 }