Install barback from a hosted source in all tests.

test/build/allows_arbitrary_modes_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 '../descriptor.dart' as d;
 import '../test_pub.dart';
 
 const TRANSFORMER = """
@@ skipping 11 matching lines @@
     return new Future.value().then((_) {
       var id = transform.primaryInput.id.changeExtension(".out");
       transform.addOutput(new Asset.fromString(id, settings.mode.toString()));
     });
   }
 }
 """;
 
 main() {
   integration("allows user-defined mode names", () {
+    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", TRANSFORMER)
       ])]),
       d.dir("web", [
         d.file("foo.txt", "foo")
       ])
     ]).create();
 
-    createLockFile('myapp', pkg: ['barback']);
-
+    pubGet();
     schedulePub(args: ["build", "--mode", "depeche"]);
 
     d.dir(appPath, [
       d.dir('build', [
         d.dir('web', [
           d.file('foo.out', 'depeche')
         ])
       ])
     ]).validate();
   });
 }