Use the new test runner.

test/transformer/exclusion/exclude_asset_prefix_test.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS d.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 pub_tests;
 
 import '../../descriptor.dart' as d;
 import '../../test_pub.dart';
 import '../../serve/utils.dart';
 
 main() {
-  initConfig();
   withBarbackVersions("any", () {
     integration("allows a directory prefix to exclude", () {
       d.dir(appPath, [
         d.pubspec({
           "name": "myapp",
           "transformers": [
             {
               "myapp/src/transformer": {
                 "\$exclude": "web/sub"
               }
@@ skipping 19 matching lines @@
 
       pubServe();
       requestShouldSucceed("foo.out", "foo.out");
       requestShouldSucceed("bar.out", "bar.out");
       requestShouldSucceed("subbub/foo.out", "foo.out");
       requestShould404("sub/foo.out");
       endPubServe();
     });
   });
 }