anchor.diff:      describe("when provider returns list of assets", () {
         beforeEach(() => buildTransformer(
             htmlWithCss,
  -          assets: [createAsset("images/icons/info.png"), createAsset("images/icons/star.png")],
  +          assets: [createAsset("web/images/icons/info.png"), createAsset("web/images/icons/star.png")],
             spriteSheet: new SpriteSheet("spritesheet", [
               new Sprite("info.png", new Image(100, 100), new Point(0, 0)),
               new Sprite("star.png", new Image(100, 100), new Point(0, 100))
             ])));
   
  -      it("adds an output for images/icons.css", () {
  +      it("adds an output for web/images/icons.css", () {
           transformer.apply(transform).then(expectAsync((_) {
  -          var expectation = _expectAsset(new AssetId("my_package", "images/icons.css"));
  +          var expectation = _expectAsset(new AssetId("my_package", "web/images/icons.css"));
             transform.getLogs(callsTo("addOutput", expectation)).verify(happenedOnce);
           }));
         });
   
  -      it("adds an output for images/icons.png", () {
  +      it("adds an output for web/images/icons.png", () {
           transformer.apply(transform).then(expectAsync((_) {
  -          var expectation = _expectAsset(new AssetId("my_package", "images/icons.png"));
  +          var expectation = _expectAsset(new AssetId("my_package", "web/images/icons.png"));
             transform.getLogs(callsTo("addOutput", expectation)).verify(happenedOnce);
           }));
         });
  
positive.code: 
        it("requests provider for assets", () {
          transformer.apply(transform).then(expectAsync((_) => provider
              .getLogs(callsTo("call", new AssetId("my_package", "images/icons.css")))
              .verify(happenedOnce)));
        });
      });
  
negative.code: import 'package:image/image.dart';
  
  void main() => describe("HtmlInspector", () {
    HtmlInspector transformer;
  
    Asset createAsset(String path, [String content]) {
      return new Asset.fromString(new AssetId("my_package", path), content);
  