Support passing configuration data to a transformer plugin.

sdk/lib/_internal/pub/test/serve/fails_to_load_an_unconfigurable_transformer_when_config_is_passed_test.dart

Index: sdk/lib/_internal/pub/test/serve/fails_to_load_an_unconfigurable_transformer_when_config_is_passed_test.dart
diff --git a/sdk/lib/_internal/pub/test/serve/fails_to_load_a_file_that_defines_no_transforms_test.dart b/sdk/lib/_internal/pub/test/serve/fails_to_load_an_unconfigurable_transformer_when_config_is_passed_test.dart
similarity index 61%
copy from sdk/lib/_internal/pub/test/serve/fails_to_load_a_file_that_defines_no_transforms_test.dart
copy to sdk/lib/_internal/pub/test/serve/fails_to_load_an_unconfigurable_transformer_when_config_is_passed_test.dart
index a636fcdb344e1a0bfae5252aa102e3402f1ffd17..04036416e457228b69fc509fbbea1b771c4f4bf6 100644
--- a/sdk/lib/_internal/pub/test/serve/fails_to_load_a_file_that_defines_no_transforms_test.dart
+++ b/sdk/lib/_internal/pub/test/serve/fails_to_load_an_unconfigurable_transformer_when_config_is_passed_test.dart
@@ -8,29 +8,28 @@ import 'package:scheduled_test/scheduled_test.dart';
 
 import '../descriptor.dart' as d;
 import '../test_pub.dart';
+import 'utils.dart';
 
 main() {
   initConfig();
 
-  integration("fails to load a file that defines no transforms", () {
+  integration("fails to load an unconfigurable transformer when config is "
+      "passed", () {
     d.dir(appPath, [
       d.pubspec({
         "name": "myapp",
-        "transformers": ["myapp/transformer"]
+        "transformers": [{"myapp/src/transformer": {'foo': 'bar'}}]
       }),
-      d.dir("lib", [
-        d.file("transformer.dart", "library does_nothing;")
-      ])
+      d.dir("lib", [d.dir("src", [
+        d.file("transformer.dart", REWRITE_TRANSFORMER)
+      ])])
     ]).create();
 
     createLockFile('myapp', pkg: ['barback']);
 
     var pub = startPub(args: ['serve', '--port=0']);
-    expect(pub.nextErrLine(), completion(startsWith('No transformers were '
-       'defined in ')));
-    expect(pub.nextErrLine(), completion(startsWith('required by myapp.')));
+    expect(pub.nextErrLine(), completion(startsWith('No transformers that '
+        'accept configuration were defined in ')));
     pub.shouldExit(1);
-    expect(pub.remainingStderr(),
-        completion(isNot(contains('This is an unexpected error'))));
   });
 }