Expand barback's notion of dirtiness to understand declaredness.

pkg/barback/test/package_graph/lazy_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.lazy_asset_test;
 
 import 'package:barback/barback.dart';
 import 'package:barback/src/utils.dart';
 import 'package:scheduled_test/scheduled_test.dart';
 
@@ skipping 336 matching lines @@
 
     updateSources(["app|foo.txt"]);
     expectNoAsset("app|foo.blab");
 
     // Getting all assets will force every lazy transformer. This shouldn't
     // cause the rewrite to apply, because foo.txt isn't primary.
     expectAllAssets(["app|foo.txt"]);
     buildShouldSucceed();
   });
 
+  test("a lazy transformer that generates fewer outputs than it declares is "
+      "forced when a declared but ungenerated output is requested", () {
+    initGraph({"app|foo.txt": "no"}, {"app": [
+      [new LazyCheckContentAndRenameTransformer(
+          oldExtension: "txt", oldContent: "yes",
+          newExtension: "out", newContent: "done")]
+    ]});
+
+    updateSources(["app|foo.txt"]);
+    expectNoAsset("app|foo.out");
+    buildShouldSucceed();
+
+    modifyAsset("app|foo.txt", "yes");
+    updateSources(["app|foo.txt"]);
+    expectAsset("app|foo.out", "done");
+    buildShouldSucceed();
+  });
+
   // Regression tests.
 
   test("a lazy transformer that doesn't apply updates its passed-through asset",
       () {
     initGraph(["app|foo.txt"], {"app": [
       [new LazyRewriteTransformer("blub", "blab")]
     ]});
 
     // Pause the provider so that the transformer will start forwarding the
     // asset while it's dirty.
@@ skipping 36 matching lines @@
     buildShouldSucceed();
 
     // [assets] should run once for each time foo.in was updated.
     expect(assets.numRuns, completion(equals(2)));
 
     // [rewrite] should run once against [assets]'s original output and once
     // against its new output.
     expect(rewrite.numRuns, completion(equals(2)));
   });
 }