Install barback from a hosted source in all tests.

test/transformer/configuration/with_configuration_only_instantiates_configurable_transformers_test.dart

Index: test/transformer/configuration/with_configuration_only_instantiates_configurable_transformers_test.dart
diff --git a/test/transformer/configuration/with_configuration_only_instantiates_configurable_transformers_test.dart b/test/transformer/configuration/with_configuration_only_instantiates_configurable_transformers_test.dart
index 000c8b552a7f4029db65d754cf5f5310b5363836..6b480c5bc74fd5a901504c22d303f41d4bdc6a78 100644
--- a/test/transformer/configuration/with_configuration_only_instantiates_configurable_transformers_test.dart
+++ b/test/transformer/configuration/with_configuration_only_instantiates_configurable_transformers_test.dart
@@ -49,12 +49,15 @@ class RewriteTransformer extends Transformer {
 main() {
    integration("with configuration, only instantiates configurable "
        "transformers", () {
+     serveBarback();
+
      var configuration = {"param": ["list", "of", "values"]};
 
      d.dir(appPath, [
        d.pubspec({
          "name": "myapp",
-         "transformers": [{"myapp/src/transformer": configuration}]
+         "transformers": [{"myapp/src/transformer": configuration}],
+         "dependencies": {"barback": "any"}
        }),
        d.dir("lib", [d.dir("src", [
          d.file("transformer.dart", transformer)
@@ -64,8 +67,7 @@ main() {
        ])
      ]).create();
 
-     createLockFile('myapp', pkg: ['barback']);
-
+     pubGet();
      var server = pubServe();
      requestShouldSucceed("foo.json", JSON.encode(configuration));
      requestShould404("foo.out");