Run pub tests against older versions of barback.

sdk/lib/_internal/pub/test/transformer/configuration/passes_configuration_to_a_transformer_test.dart

Index: sdk/lib/_internal/pub/test/transformer/configuration/passes_configuration_to_a_transformer_test.dart
diff --git a/sdk/lib/_internal/pub/test/transformer/configuration/passes_configuration_to_a_transformer_test.dart b/sdk/lib/_internal/pub/test/transformer/configuration/passes_configuration_to_a_transformer_test.dart
index 48cf45ad44f0e52f74da497f4b36416b4709902c..180baa2dfd0af559d81fbf89024ac03f1fbfe7fe 100644
--- a/sdk/lib/_internal/pub/test/transformer/configuration/passes_configuration_to_a_transformer_test.dart
+++ b/sdk/lib/_internal/pub/test/transformer/configuration/passes_configuration_to_a_transformer_test.dart
@@ -35,26 +35,28 @@ class ConfigTransformer extends Transformer {
 
 main() {
   initConfig();
-  integration("passes configuration to a transformer", () {
-    var configuration = {"param": ["list", "of", "values"]};
-
-    d.dir(appPath, [
-      d.pubspec({
-        "name": "myapp",
-        "transformers": [{"myapp/src/transformer": configuration}]
-      }),
-      d.dir("lib", [d.dir("src", [
-        d.file("transformer.dart", transformer)
-      ])]),
-      d.dir("web", [
-        d.file("foo.txt", "foo")
-      ])
-    ]).create();
-
-    createLockFile('myapp', pkg: ['barback']);
-
-    var server = pubServe();
-    requestShouldSucceed("foo.json", JSON.encode(configuration));
-    endPubServe();
+  withBarbackVersions("any", () {
+    integration("passes configuration to a transformer", () {
+      var configuration = {"param": ["list", "of", "values"]};
+
+      d.dir(appPath, [
+        d.pubspec({
+          "name": "myapp",
+          "transformers": [{"myapp/src/transformer": configuration}]
+        }),
+        d.dir("lib", [d.dir("src", [
+          d.file("transformer.dart", transformer)
+        ])]),
+        d.dir("web", [
+          d.file("foo.txt", "foo")
+        ])
+      ]).create();
+
+      createLockFile('myapp', pkg: ['barback']);
+
+      var server = pubServe();
+      requestShouldSucceed("foo.json", JSON.encode(configuration));
+      endPubServe();
+    });
   });
 }