Drop support for older Barback versions.

test/transformer/asset_not_found_exceptions_are_detectable_test.dart

Index: test/transformer/asset_not_found_exceptions_are_detectable_test.dart
diff --git a/test/transformer/asset_not_found_exceptions_are_detectable_test.dart b/test/transformer/asset_not_found_exceptions_are_detectable_test.dart
index 86d7d3ff10142af6c0e87c0f4066f6128fb1ba4c..3dfcfa469141e064cf048e6019e5d30d08af71f2 100644
--- a/test/transformer/asset_not_found_exceptions_are_detectable_test.dart
+++ b/test/transformer/asset_not_found_exceptions_are_detectable_test.dart
@@ -38,33 +38,31 @@ class GetInputTransformer extends Transformer {
 """;
 
 main() {
-  withBarbackVersions("any", () {
-    integration("AssetNotFoundExceptions are detectable", () {
-      d.dir(appPath, [
-        d.pubspec({
-          "name": "myapp",
-          "transformers": ["myapp/src/transformer"]
-        }),
-        d.dir("lib", [d.dir("src", [
-          d.file("transformer.dart", transformer)
-        ])]),
-        d.dir("web", [
-          d.file("foo.txt", "foo")
-        ])
-      ]).create();
+  integration("AssetNotFoundExceptions are detectable", () {
+    d.dir(appPath, [
+      d.pubspec({
+        "name": "myapp",
+        "transformers": ["myapp/src/transformer"]
+      }),
+      d.dir("lib", [d.dir("src", [
+        d.file("transformer.dart", transformer)
+      ])]),
+      d.dir("web", [
+        d.file("foo.txt", "foo")
+      ])
+    ]).create();
 
-      createLockFile('myapp', pkg: ['barback']);
+    createLockFile('myapp', pkg: ['barback']);
 
-      var server = pubServe();
-      requestShouldSucceed("foo.txt", JSON.encode({
-        "package": "myapp",
-        "path": "nonexistent"
-      }));
-      endPubServe();
+    var server = pubServe();
+    requestShouldSucceed("foo.txt", JSON.encode({
+      "package": "myapp",
+      "path": "nonexistent"
+    }));
+    endPubServe();
 
-      // Since the AssetNotFoundException was caught and handled, the server
-      // shouldn't print any error information for it.
-      server.stderr.expect(isDone);
-    });
+    // Since the AssetNotFoundException was caught and handled, the server
+    // shouldn't print any error information for it.
+    server.stderr.expect(isDone);
   });
 }