Fix a deadlock.

test/package_graph/declaring_transformer_test.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.package_graph.declaring_transformer_test;
 
 import 'package:barback/barback.dart';
 import 'package:barback/src/utils.dart';
 import 'package:scheduled_test/scheduled_test.dart';
 
@@ skipping 147 matching lines @@
 
     transformer.pauseApply();
     updateSources(["app|foo.blub"]);
     expectAssetDoesNotComplete("app|foo.blub");
 
     transformer.resumeApply();
     expectAsset("app|foo.blub", "foo.blub");
     buildShouldSucceed();
   });
 
+  // Regression test for #64.
+  test("a declaring transformer's output passes through a lazy transformer",
+      () {
+    var declaring = new DeclaringRewriteTransformer("one", "two");
+    initGraph(["app|foo.one"], {"app": [
+      [declaring],
+      [new LazyRewriteTransformer("two", "three")]
+    ]});
+
+    updateSources(["app|foo.one"]);
+    // Give the transformers time to declare their assets.
+    schedule(pumpEventQueue);
+
+    expectAsset("app|foo.one", "foo");
+    expectAsset("app|foo.two", "foo.two");
+    expectAsset("app|foo.three", "foo.two.three");
+    buildShouldSucceed();
+
+    modifyAsset("app|foo.one", "bar");
+    updateSources(["app|foo.one"]);
+
+    expectAsset("app|foo.one", "bar");
+    expectAsset("app|foo.two", "bar.two");
+    expectAsset("app|foo.three", "bar.two.three");
+    buildShouldSucceed();
+
+    expect(declaring.numRuns, completion(equals(2)));
+  });
+
   test("a declaring transformer following a lazy transformer runs eagerly once "
       "its input is available", () {
     var declaring = new DeclaringRewriteTransformer("two", "three");
     initGraph(["app|foo.in"], {"app": [
       [new LazyAssetsTransformer(["app|out.one", "app|out.two"])],
       [declaring]
     ]});
 
     updateSources(["app|foo.in"]);
     // Give the transformers time to declare their assets.
@@ skipping 155 matching lines @@
   test("can declare outputs it doesn't emit", () {
     initGraph(["app|foo.txt"], {"app": [
       [new DeclareAssetsTransformer(["app|out.txt"], emitted: [])]
     ]});
 
     updateSources(["app|foo.txt"]);
     expectNoAsset("app|out.txt");
     buildShouldSucceed();
   });
 }