Install barback from a hosted source in all tests.

test/serve/native_watch_replaced_file_test.dart

 // Copyright (c) 2013, 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 'dart:async';
 import 'dart:io';
 
 import 'package:path/path.dart' as p;
 import 'package:scheduled_test/scheduled_test.dart';
 
 import '../descriptor.dart' as d;
 import '../test_pub.dart';
 import 'utils.dart';
 
 main() {
   // This is a regression test for http://dartbug.com/21402.
    integration("picks up files replaced after serving started when using the "
        "native watcher", () {
+     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", REWRITE_TRANSFORMER)
        ])]),
        d.dir("web", [
          d.file("file.txt", "before"),
        ]),
        d.file("other", "after")
      ]).create();
 
-     createLockFile("myapp", pkg: ["barback"]);
-
+     pubGet();
      pubServe(args: ["--no-force-poll"]);
      waitForBuildSuccess();
      requestShouldSucceed("file.out", "before.out");
 
      schedule(() {
        // Replace file.txt by renaming other on top of it.
        return new File(p.join(sandboxDir, appPath, "other"))
            .rename(p.join(sandboxDir, appPath, "web", "file.txt"));
      });
 
      // Read the transformed file to ensure the change is actually noticed by
      // pub and not that we just get the new file contents piped through
      // without pub realizing they've changed.
      waitForBuildSuccess();
      requestShouldSucceed("file.out", "after.out");
 
      endPubServe();
    });
 }