Support using a mock SDK with the resolver in code-transformers, and switch

pkg/code_transformers/test/resolver_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 code_transformers.test.resolver_test;
 
 import 'dart:async';
 
 import 'package:barback/barback.dart';
 import 'package:code_transformers/resolver.dart';
 import 'package:code_transformers/tests.dart';
 import 'package:unittest/compact_vm_config.dart';
 import 'package:unittest/unittest.dart';
 
 main() {
   useCompactVMConfiguration();
+  group('mock sdk', () {
+    resolverTests(new Resolvers.fromMock({
+      'dart:core': 'library dart.core;\nclass Object {}',
+      'dart:async': 'library dart.async;',
+      'dart:html': 'library dart.html;',
+    }));
+  });
+
+  group('real sdk', () {
+    resolverTests(new Resolvers.fromSdkDirectory(testingDartSdkDirectory));
+  });
+}
+
+resolverTests(Resolvers resolvers) {
   var entryPoint = new AssetId('a', 'web/main.dart');
-  var resolvers = new Resolvers(testingDartSdkDirectory);
-
   Future validateResolver({Map<String, String> inputs, validator(Resolver),
       List<String> messages: const[]}) {
     return applyTransformers(
           [[new TestTransformer(resolvers, entryPoint, validator)]],
           inputs: inputs,
           messages: messages);
   }
 
   group('Resolver', () {
 
@@ skipping 326 matching lines @@
 
   // TODO(nweiz): This should just take an AssetId when barback <0.13.0 support
   // is dropped.
   Future<bool> isPrimary(idOrAsset) {
     var id = idOrAsset is AssetId ? idOrAsset : idOrAsset.id;
     return new Future.value(id == primary);
   }
 
   applyResolver(Transform transform, Resolver resolver) => validator(resolver);
 }