Make Transform a little more pleasant to use:

pkg/barback/test/transformer/mock.dart

Index: pkg/barback/test/transformer/mock.dart
diff --git a/pkg/barback/test/transformer/mock.dart b/pkg/barback/test/transformer/mock.dart
index 088700277a7a0ad8d03ad34b7fbe17b3e60f31ea..7955d3f38670ad4598a5a48a176e537cd44d184b 100644
--- a/pkg/barback/test/transformer/mock.dart
+++ b/pkg/barback/test/transformer/mock.dart
@@ -129,12 +129,6 @@ abstract class MockTransformer extends Transformer {
     }).then((_) => transform.getInput(id));
   }
 
-  /// Like [Transform.primaryInput], but respects [pauseGetInput].
-  ///
-  /// This is intended for use by subclasses of [MockTransformer].
-  Future<Asset> getPrimary(Transform transform) =>

[nweiz, 2013/08/28 19:29:43]

We should keep this around so [pauseGetInput] still works for primary inputs.

[Bob Nystrom, 2013/08/28 20:51:27]

Done, but modified to actually call primaryInput instead of just getInput() to
cover that code path.

-      getInput(transform, transform.primaryId);
-
   Future<bool> isPrimary(Asset asset) {
     return newFuture(() => doIsPrimary(asset)).then((result) {
       return newFuture(() {