Run pub tests against older versions of barback.

third_party/pkg/barback-0.13.0/test/transformer/lazy_bad.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.transformer.lazy_bad;
 
+import 'dart:async';
+
 import 'package:barback/barback.dart';
+import 'package:barback/src/utils.dart';
 
 import 'mock.dart';
 
 /// A lazy transformer that throws an exception after [declareOutputs].
 class LazyBadTransformer extends MockTransformer implements LazyTransformer {
   /// The error [this] throws.
   static const ERROR = "I am a bad transformer!";
 
   /// The asset name that [this] should output.
   final String output;
 
   LazyBadTransformer(this.output);
 
-  bool doIsPrimary(AssetId id) => true;
+  Future<bool> doIsPrimary(_) => new Future.value(true);
 
-  void doApply(Transform transform) {
-    var id = new AssetId.parse(output);
-    transform.addOutput(new Asset.fromString(id, output));
+  Future doApply(Transform transform) {
+    return newFuture(() {
+      var id = new AssetId.parse(output);
+      transform.addOutput(new Asset.fromString(id, output));
+    });
   }
 
-  void declareOutputs(DeclaringTransform transform) {
-    var id = new AssetId.parse(output);
-    transform.declareOutput(id);
-    throw ERROR;
+  Future declareOutputs(DeclaringTransform transform) {
+    return newFuture(() {
+      var id = new AssetId.parse(output);
+      transform.declareOutput(id);
+      throw ERROR;
+    });
   }
 }