Support JSON output for pub build.

sdk/lib/_internal/pub/test/build/outputs_error_to_json_test.dart

Index: sdk/lib/_internal/pub/test/build/outputs_error_to_json_test.dart
diff --git a/sdk/lib/_internal/pub/test/transformer/can_use_read_input_test.dart b/sdk/lib/_internal/pub/test/build/outputs_error_to_json_test.dart
similarity index 50%
copy from sdk/lib/_internal/pub/test/transformer/can_use_read_input_test.dart
copy to sdk/lib/_internal/pub/test/build/outputs_error_to_json_test.dart
index fba1eed718ec25ea170930a19ddaa6b9f38e3393..bb522acd236bbe6e3806c7343efca8b3747cecc7 100644
--- a/sdk/lib/_internal/pub/test/transformer/can_use_read_input_test.dart
+++ b/sdk/lib/_internal/pub/test/build/outputs_error_to_json_test.dart
@@ -1,12 +1,14 @@
-// Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS d.file
+// Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS d.file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library pub_tests;
 
+import 'package:scheduled_test/scheduled_test.dart';
+
+import '../../lib/src/exit_codes.dart' as exit_codes;
 import '../descriptor.dart' as d;
 import '../test_pub.dart';
-import '../serve/utils.dart';
 
 const TRANSFORMER = """
 import 'dart:async';
@@ -18,28 +20,21 @@ class RewriteTransformer extends Transformer {
 
   String get allowedExtensions => '.txt';
 
-  Future apply(Transform transform) {
-    return transform.readInput(transform.primaryInput.id).toList()
-        .then((contents) {
-      var id = transform.primaryInput.id.changeExtension(".out");
-      var asset = new Asset.fromString(id, "\$contents.out");
-      transform.addOutput(asset);
-    });
-  }
+  Future apply(Transform transform) => throw new Exception('oh no!');
 }
 """;
 
 main() {
   initConfig();
-  integration("a transform can use readInputAsString", () {
+  integration("outputs error to JSON in a failed build", () {
     d.dir(appPath, [
       d.pubspec({
         "name": "myapp",
-        "transformers": ["myapp/src/transformer"]
+        "transformers": ["myapp"]
       }),
-      d.dir("lib", [d.dir("src", [
+      d.dir("lib", [
         d.file("transformer.dart", TRANSFORMER)
-      ])]),
+      ]),
       d.dir("web", [
         d.file("foo.txt", "foo")
       ])
@@ -47,8 +42,17 @@ main() {
 
     createLockFile('myapp', pkg: ['barback']);
 
-    pubServe();
-    requestShouldSucceed("foo.out", "[[102, 111, 111]].out");
-    endPubServe();
+    schedulePub(args: ["build", "--format", "json"],
+        outputJson: {
+          "buildResult": "failure",
+          "errors": [
+            {
+              "error": startsWith(
+                  "Transform Rewrite on myapp|web/foo.txt threw error: oh no!")
+            }
+          ],
+          "log": []
+        },
+        exitCode: exit_codes.DATA);
   });
 }