Binary assets and more unit tests for Asset.

pkg/barback/test/utils.dart

 // Copyright (c) 2013, 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 barback.test.utils;
 
 import 'dart:async';
 import 'dart:collection';
+import 'dart:io';
 
 import 'package:barback/barback.dart';
 import 'package:barback/src/asset_graph.dart';
 import 'package:pathos/path.dart' as pathos;
 import 'package:scheduled_test/scheduled_test.dart';
 
 // TODO(rnystrom): Get rid of this or find a better path for it.
 import '../../../sdk/lib/_internal/pub/test/command_line_config.dart';
 
 var _configured = false;
@@ skipping 431 matching lines @@
   }
 }
 
 /// An implementation of [Asset] that never hits the file system.
 class MockAsset implements Asset {
   final AssetId id;
   String contents;
 
   MockAsset(this.id, this.contents);
 
-  Future<String> readAsString() => new Future.value(contents);
+  Future<String> readAsString({Encoding encoding}) =>
+      new Future.value(contents);
+
   Stream<List<int>> read() => throw new UnimplementedError();
 
-  serialize() => throw new UnimplementedError();
-
   String toString() => "MockAsset $id $contents";
 }