Install barback from a hosted source in all tests.

test/global/run/runs_transformer_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';
 
 const TRANSFORMER = """
 import 'dart:async';
 
 import 'package:barback/barback.dart';
 
 class DartTransformer extends Transformer {
   DartTransformer.asPlugin();
 
   String get allowedExtensions => '.in';
 
   void apply(Transform transform) {
     transform.addOutput(new Asset.fromString(
         new AssetId("foo", "bin/script.dart"),
         "void main() => print('generated');"));
   }
 }
 """;
 
 main() {
   integration('runs a global script generated by a transformer', () {
-    makeGlobalPackage("foo", "1.0.0", [
-      d.pubspec({
-        "name": "foo",
-        "version": "1.0.0",
-        "transformers": ["foo/src/transformer"]
-      }),
-      d.dir("lib", [d.dir("src", [
-        d.file("transformer.dart", TRANSFORMER),
-        d.file("primary.in", "")
-      ])])
-    ], pkg: ['barback']);
+    servePackages((builder) {
+      builder.serveRealPackage("barback");
+
+      builder.serve("foo", "1.0.0",
+          pubspec: {"transformers": ["foo/src/transformer"]},
+          deps: {"barback": "any"},
+          contents: [
+            d.dir("lib", [d.dir("src", [
+              d.file("transformer.dart", TRANSFORMER),
+              d.file("primary.in", "")
+            ])])
+          ]);
+    });
+
+    schedulePub(args: ["global", "activate", "foo"]);
 
     var pub = pubRun(global: true, args: ["foo:script"]);
-
     pub.stdout.expect("generated");
     pub.shouldExit();
   });
 }