Install barback from a hosted source in all tests.

test/transformer/fails_to_load_a_file_that_defines_no_transforms_test.dart

Index: test/transformer/fails_to_load_a_file_that_defines_no_transforms_test.dart
diff --git a/test/transformer/fails_to_load_a_file_that_defines_no_transforms_test.dart b/test/transformer/fails_to_load_a_file_that_defines_no_transforms_test.dart
index b42899399f91ce4dfcf9cc63817a5201066d2d87..bd0ba2c043be5982f0d20072743a2074f2721adc 100644
--- a/test/transformer/fails_to_load_a_file_that_defines_no_transforms_test.dart
+++ b/test/transformer/fails_to_load_a_file_that_defines_no_transforms_test.dart
@@ -13,18 +13,20 @@ import '../serve/utils.dart';
 
 main() {
   integration("fails to load a file that defines no transforms", () {
+    serveBarback();
+
     d.dir(appPath, [
       d.pubspec({
         "name": "myapp",
-        "transformers": ["myapp/transformer"]
+        "transformers": ["myapp/transformer"],
+        "dependencies": {"barback": "any"}
       }),
       d.dir("lib", [
         d.file("transformer.dart", "library does_nothing;")
       ])
     ]).create();
 
-    createLockFile('myapp', pkg: ['barback']);
-
+    pubGet();
     var pub = startPubServe();
     pub.stderr.expect(startsWith('No transformers were defined in '));
     pub.stderr.expect(startsWith('required by myapp.'));