Install barback from a hosted source in all tests.

test/serve/supports_user_defined_lazy_transformers_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 'utils.dart';
 
 main() {
   integration("supports a user-defined lazy transformer", () {
+    serveBarback();
+
     d.dir(appPath, [
       d.pubspec({
         "name": "myapp",
-        "transformers": ["myapp/src/transformer"]
+        "transformers": ["myapp/src/transformer"],
+        "dependencies": {"barback": "any"}
       }),
       d.dir("lib", [d.dir("src", [
         d.file("transformer.dart", LAZY_TRANSFORMER)
       ])]),
       d.dir("web", [
         d.file("foo.txt", "foo")
       ])
     ]).create();
 
-    createLockFile('myapp', pkg: ['barback']);
-
+    pubGet();
     var server = pubServe();
     // The build should complete without the transformer logging anything.
     server.stdout.expect('Build completed successfully');
 
     requestShouldSucceed("foo.out", "foo.out");
     server.stdout.expect(emitsLines(
         '[Info from LazyRewrite]:\n'
         'Rewriting myapp|web/foo.txt.'));
     endPubServe();
   });
 }