Install barback from a hosted source in all tests.

test/run/runs_transformer_in_entrypoint_test.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS 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.
 
 import '../descriptor.dart' as d;
 import '../test_pub.dart';
 import '../serve/utils.dart';
 
 const SCRIPT = """
 const TOKEN = "hi";
 main() {
   print(TOKEN);
 }
 """;
 
 main() {
   integration('runs transformers in the entrypoint package', () {
+    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", dartTransformer("transformed"))
       ])]),
       d.dir("bin", [
         d.file("hi.dart", SCRIPT)
       ])
     ]).create();
 
-    createLockFile('myapp', pkg: ['barback']);
-
+    pubGet();
     var pub = pubRun(args: ["bin/hi"]);
 
     pub.stdout.expect("(hi, transformed)");
     pub.shouldExit();
   });
 }