Run pub tests against older versions of barback.

third_party/pkg/barback-0.13.0/test/transformer/lazy_bad.dart

Index: third_party/pkg/barback-0.13.0/test/transformer/lazy_bad.dart
diff --git a/pkg/barback/test/transformer/lazy_bad.dart b/third_party/pkg/barback-0.13.0/test/transformer/lazy_bad.dart
similarity index 58%
copy from pkg/barback/test/transformer/lazy_bad.dart
copy to third_party/pkg/barback-0.13.0/test/transformer/lazy_bad.dart
index 93fc8d803a0f7240c401a615257c46fb68381557..16d0b77f0024a7a97d8e37d526a6b7660ba5f0ff 100644
--- a/pkg/barback/test/transformer/lazy_bad.dart
+++ b/third_party/pkg/barback-0.13.0/test/transformer/lazy_bad.dart
@@ -4,7 +4,10 @@
 
 library barback.test.transformer.lazy_bad;
 
+import 'dart:async';
+
 import 'package:barback/barback.dart';
+import 'package:barback/src/utils.dart';
 
 import 'mock.dart';
 
@@ -18,16 +21,20 @@ class LazyBadTransformer extends MockTransformer implements LazyTransformer {
 
   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;
+    });
   }
 }