Install barback from a hosted source in all tests.

test/run/runs_transformer_in_entrypoint_test.dart

Index: test/run/runs_transformer_in_entrypoint_test.dart
diff --git a/test/run/runs_transformer_in_entrypoint_test.dart b/test/run/runs_transformer_in_entrypoint_test.dart
index ca53a2a09dd514b0ec61ff5c0535fba917f77791..9a773ab227aad388a5cf8d0f3998da925d3b52ea 100644
--- a/test/run/runs_transformer_in_entrypoint_test.dart
+++ b/test/run/runs_transformer_in_entrypoint_test.dart
@@ -15,10 +15,13 @@ main() {
 
 main() {
   integration('runs transformers in the entrypoint package', () {
+    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", dartTransformer("transformed"))
@@ -28,8 +31,7 @@ main() {
       ])
     ]).create();
 
-    createLockFile('myapp', pkg: ['barback']);
-
+    pubGet();
     var pub = pubRun(args: ["bin/hi"]);
 
     pub.stdout.expect("(hi, transformed)");