Run pub tests against older versions of barback.

third_party/pkg/barback-0.13.0/test/transformer/bad_log.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 barback.test.transformer.bad_log;
 
+import 'dart:async';
+
 import 'package:barback/barback.dart';
+import 'package:barback/src/utils.dart';
 
 import 'mock.dart';
 
 /// A transformer that logs an error when run, Before generating the given
 /// outputs.
 class BadLogTransformer extends MockTransformer {
   /// The list of asset names that it should output.
   final List<String> outputs;
 
   BadLogTransformer(this.outputs);
 
-  bool doIsPrimary(AssetId id) => true;
+  Future<bool> doIsPrimary(AssetId id) => new Future.value(true);
 
-  void doApply(Transform transform) {
-    transform.logger.error("first error");
-    transform.logger.error("second error");
+  Future doApply(Transform transform) {
+    return newFuture(() {
+      transform.logger.error("first error");
+      transform.logger.error("second error");
 
-    for (var output in outputs) {
-      var id = new AssetId.parse(output);
-      transform.addOutput(new Asset.fromString(id, output));
-    }
+      for (var output in outputs) {
+        var id = new AssetId.parse(output);
+        transform.addOutput(new Asset.fromString(id, output));
+      }
+    });
   }
 }