Run pub tests against older versions of barback.

sdk/lib/_internal/pub/test/transformer/prefers_transformer_to_library_name_test.dart

Index: sdk/lib/_internal/pub/test/transformer/prefers_transformer_to_library_name_test.dart
diff --git a/sdk/lib/_internal/pub/test/transformer/prefers_transformer_to_library_name_test.dart b/sdk/lib/_internal/pub/test/transformer/prefers_transformer_to_library_name_test.dart
index f116bd4be53ddb467f7bff72194ac01fa26e9c68..b28506cc23a6e04958d1b554c5c2e7322d2e17e3 100644
--- a/sdk/lib/_internal/pub/test/transformer/prefers_transformer_to_library_name_test.dart
+++ b/sdk/lib/_internal/pub/test/transformer/prefers_transformer_to_library_name_test.dart
@@ -29,26 +29,28 @@ class RewriteTransformer extends Transformer {
 
 main() {
   initConfig();
-  integration("prefers transformer.dart to <package name>.dart", () {
-    d.dir(appPath, [
-      d.pubspec({
-        "name": "myapp",
-        "transformers": ["myapp"]
-      }),
-      d.dir("lib", [
-        d.file("transformer.dart", REWRITE_TRANSFORMER),
-        d.file("myapp.dart", WRONG_TRANSFORMER)
-      ]),
-      d.dir("web", [
-        d.file("foo.txt", "foo")
-      ])
-    ]).create();
-
-    createLockFile('myapp', pkg: ['barback']);
-
-    pubServe();
-    requestShouldSucceed("foo.out", "foo.out");
-    requestShould404("foo.wrong");
-    endPubServe();
+  withBarbackVersions("any", () {
+    integration("prefers transformer.dart to <package name>.dart", () {
+      d.dir(appPath, [
+        d.pubspec({
+          "name": "myapp",
+          "transformers": ["myapp"]
+        }),
+        d.dir("lib", [
+          d.file("transformer.dart", REWRITE_TRANSFORMER),
+          d.file("myapp.dart", WRONG_TRANSFORMER)
+        ]),
+        d.dir("web", [
+          d.file("foo.txt", "foo")
+        ])
+      ]).create();
+
+      createLockFile('myapp', pkg: ['barback']);
+
+      pubServe();
+      requestShouldSucceed("foo.out", "foo.out");
+      requestShould404("foo.wrong");
+      endPubServe();
+    });
   });
 }