anchor.diff:        var handler = packagesHandler();
         var request = new Request(
             "GET",
  -          Uri.parse(
  -              "http://example.com/shelf_packages_handler/"
  +          Uri.parse("http://example.com/shelf_packages_handler/"
                 "shelf_packages_handler.dart"));
         var response = await handler(request);
         expect(response.statusCode, equals(200));
  -      expect(await response.readAsString(),
  -          contains("Handler packagesHandler"));
  +      expect(
  +          await response.readAsString(), contains("Handler packagesHandler"));
       });
   
       group("with a package root", () {
  
positive.code: void main() {
    var dir;
    setUp(() {
      dir = Directory.systemTemp
          .createTempSync("shelf_packages_handler_test")
          .path;
      new Directory(dir).createSync();
      new Directory("$dir/foo").createSync();
      new File("$dir/foo/foo.dart")
  
negative.code:       var handler = packagesDirHandler();
        var request = new Request(
            "GET",
            Uri.parse("http://example.com/packages/shelf_packages_handler/"
                "shelf_packages_handler.dart"));
        var response = await handler(request);
        expect(response.statusCode, equals(200));
        expect(
            await response.readAsString(), contains("Handler packagesHandler"));
      });
  
      test("supports a directory deep in the URL", () async {
        var handler = packagesDirHandler();
        var request = new Request(
            "GET",
            Uri.parse("http://example.com/foo/bar/very/deep/packages/"
                "shelf_packages_handler/shelf_packages_handler.dart"));
        var response = await handler(request);
        expect(response.statusCode, equals(200));
        expect(
            await response.readAsString(), contains("Handler packagesHandler"));
      });
  
      test("404s for a URL without a packages directory", () async {
        var handler = packagesDirHandler();
        var request = new Request(
            "GET",
            Uri.parse("http://example.com/shelf_packages_handler/"
                "shelf_packages_handler.dart"));
        var response = await handler(request);
        expect(response.statusCode, equals(404));
  