Install barback from a hosted source in all tests.

test/dart2js/compiles_imported_generated_file_test.dart

Index: test/dart2js/compiles_imported_generated_file_test.dart
diff --git a/test/dart2js/compiles_imported_generated_file_test.dart b/test/dart2js/compiles_imported_generated_file_test.dart
index 1cc4379f59ae39478b9825d0e16052de623c3cb8..30ed4b7c26999a3f32c5b60f58d5eb55d3820c19 100644
--- a/test/dart2js/compiles_imported_generated_file_test.dart
+++ b/test/dart2js/compiles_imported_generated_file_test.dart
@@ -10,11 +10,14 @@ import '../serve/utils.dart';
 
 main() {
   integration("compiles a Dart file that imports a generated file to JS", () {
+    serveBarback();
+
     d.dir(appPath, [
       d.pubspec({
         "name": "myapp",
         "version": "0.0.1",
-        "transformers": ["myapp/transformer"]
+        "transformers": ["myapp/transformer"],
+        "dependencies": {"barback": "any"}
       }),
       d.dir("lib", [
         d.file("transformer.dart", dartTransformer("munge"))
@@ -31,8 +34,7 @@ const TOKEN = "before";
       ])
     ]).create();
 
-    createLockFile('myapp', pkg: ['barback']);
-
+    pubGet();
     pubServe();
     requestShouldSucceed("main.dart.js", contains("(before, munge)"));
     endPubServe();