Barback transforms now pass through the primary input by default.

pkg/barback/test/utils.dart

Index: pkg/barback/test/utils.dart
diff --git a/pkg/barback/test/utils.dart b/pkg/barback/test/utils.dart
index 7da5977e9b7a80561ea521a74f841a8b21f23ad5..4c39848c1b9cc80c22fc05baba1999ec43f50b95 100644
--- a/pkg/barback/test/utils.dart
+++ b/pkg/barback/test/utils.dart
@@ -249,9 +249,10 @@ Future<LogEntry> _getNextLog(String description) {
 /// Schedules an expectation that the graph will deliver an asset matching
 /// [name] and [contents].
 ///
-/// If [contents] is omitted, defaults to the asset's filename without an
-/// extension (which is the same default that [initGraph] uses).
-void expectAsset(String name, [String contents]) {
+/// [contents] may be a [String] or a [Matcher] that matches a string. If
+/// [contents] is omitted, defaults to the asset's filename without an extension
+/// (which is the same default that [initGraph] uses).
+void expectAsset(String name, [contents]) {
   var id = new AssetId.parse(name);
 
   if (contents == null) {
@@ -262,7 +263,7 @@ void expectAsset(String name, [String contents]) {
     return _barback.getAssetById(id).then((asset) {
       // TODO(rnystrom): Make an actual Matcher class for this.
       expect(asset.id, equals(id));
-      expect(asset.readAsString(), completion(equals(contents)));
+      expect(asset.readAsString(), completion(contents));
     });
   }, "get asset $name");
 }